Cash Trust Series N-CSR Certified annual shareholder report (management investment company)

United States

Securities and Exchange Commission

Washington, D.C. 20549

Form N-CSR

Certified Shareholder Report of Registered Management Investment Companies

811-5843

(Investment Company Act File Number)

Cash Trust Series, Inc.

_______________________________________________________________

(Exact Name of Registrant as Specified in Charter)

Federated Investors Funds

4000 Ericsson Drive

Warrendale, Pennsylvania 15086-7561

(Address of Principal Executive Offices)

(412) 288-1900

(Registrant's Telephone Number)

John W. McGonigle, Esquire

Federated Investors Tower

1001 Liberty Avenue

Pittsburgh, Pennsylvania 15222-3779

(Name and Address of Agent for Service)

(Notices should be sent to the Agent for Service)

Date of Fiscal Year End: 05/31/15

Date of Reporting Period: 05/31/15

Item 1. Reports to Stockholders

Annual Shareholder Report

May 31, 2015

Ticker CTGXX

Federated Government Cash Series

A Portfolio of Cash Trust Series, Inc.

Not FDIC Insured
May Lose Value

No Bank Guarantee

CONTENTS

Portfolio of Investments Summary Tables	1
Portfolio of Investments	2
Financial Highlights	6
Statement of Assets and Liabilities	7
Statement of Operations	8
Statement of Changes in Net Assets	9
Notes to Financial Statements	10
Report of Independent Registered Public Accounting Firm	17
Shareholder Expense Example	18
Board of Directors and Corporation Officers	20
Evaluation and Approval of Advisory Contract	26
Voting Proxies on Fund Portfolio Securities	31
Quarterly Portfolio Schedule	31

Portfolio of Investments Summary Tables (unaudited)

At May 31, 2015, the Fund's portfolio composition¹ was as follows:

Portfolio Composition	Percentage of Total Net Assets
U.S. Government Agency Securities	40.9%
U.S. Treasury Security	1.0%
Repurchase Agreements	58.1%
Other Assets and Liabilities—Net2,3	0.0%
TOTAL	100.0%

At May 31, 2015, the Fund's effective maturity⁴ schedule was as follows:

Securities With an Effective Maturity of:	Percentage of Total Net Assets
1-7 Days	63.2%
8-30 Days	11.8%
31-90 Days	17.7%
91-180 Days	2.3%
181 Days or more	5.0%
Other Assets and Liabilities—Net2,3	0.0%
TOTAL	100.0%

1	See the Fund's Prospectus and Statement of Additional Information for a description of the principal types of securities in which the Fund invests.
2	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.
3	Represents less than 0.1%.
4	Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940, which regulates money market mutual funds.

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1

Portfolio of Investments

May 31, 2015

Principal Amount			Value
		GOVERNMENT AGENCIES—40.9%
$41,033,000	1	Federal Farm Credit System Floating Rate Notes, 0.160% - 0.215%, 6/1/2015 - 6/28/2015	$41,032,446
3,500,000		Federal Farm Credit System, 0.550%, 8/17/2015	3,502,190
27,000,000	2	Federal Home Loan Bank System Discount Notes, 0.086% - 0.138%, 7/10/2015 - 8/5/2015	26,996,483
34,000,000	1	Federal Home Loan Bank System Floating Rate Notes, 0.164% - 0.194%, 6/9/2015 - 7/27/2015	33,998,908
59,250,000		Federal Home Loan Bank System, 0.170% - 0.400%, 6/30/2015 - 3/30/2016	59,247,894
5,000,000	2	Federal Home Loan Mortgage Corp. Discount Notes, 0.090%, 6/25/2015	4,999,700
11,500,000	1	Federal Home Loan Mortgage Corp. Floating Rate Notes, 0.163% - 0.190%, 6/12/2015 - 6/16/2015	11,499,424
9,566,000		Federal Home Loan Mortgage Corp., 0.300% - 4.375%, 7/8/2015 - 7/17/2015	9,596,040
4,000,000	2	Federal National Mortgage Association Discount Notes, 0.180%, 9/1/2015	3,998,160
4,000,000	1	Federal National Mortgage Association Floating Rate Notes, 0.151%, 6/5/2015	3,999,931
5,081,000		Federal National Mortgage Association, 0.500% - 1.625%, 10/26/2015 - 3/30/2016	5,092,856
		TOTAL GOVERNMENT AGENCIES	203,964,032
		U.S. TREASURY—1.0%
5,000,000		United States Treasury Notes, 1.375%, 11/30/2015	5,029,018
		REPURCHASE AGREEMENTS—58.1%
8,000,000	3	Interest in $581,000,000 joint repurchase agreement 0.10%, dated 4/7/2015 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $581,095,219 on 6/5/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency and U.S. Treasury securities with various maturities to 4/20/2065 and the market value of those underlying securities was $593,801,016.	8,000,000
5,000,000	3	Interest in $380,000,000 joint repurchase agreement 0.10%, dated 4/29/2015 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $380,039,056 on 6/5/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency and U.S. Treasury securities with various maturities to 4/20/2065 and the market value of those underlying securities was $388,369,323.	5,000,000

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Principal Amount			Value
		REPURCHASE AGREEMENTS—continued
$6,000,000	3	Interest in $500,000,000 joint repurchase agreement 0.12%, dated 4/29/2015 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $500,056,667 on 6/2/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency and U.S. Treasury securities with various maturities to 1/20/2065 and the market value of those underlying securities was $511,305,560.	$6,000,000
3,000,000	3	Interest in $250,000,000 joint repurchase agreement 0.12%, dated 4/29/2015 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $250,029,167 on 6/3/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency and U.S. Treasury securities with various maturities to 12/1/2047 and the market value of those underlying securities was $255,913,630.	3,000,000
3,000,000	3	Interest in $250,000,000 joint repurchase agreement 0.22%, dated 3/5/2015 under which Bank of Nova Scotia will repurchase securities provided as collateral for $250,414,028 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency and U.S. Treasury securities with various maturities to 5/20/2062 and the market value of those underlying securities was $255,148,122.	3,000,000
6,000,000	3	Interest in $475,000,000 joint repurchase agreement 0.12%, dated 5/18/2015 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $475,047,500 on 6/17/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities with various maturities to 5/1/2045 and the market value of those underlying securities was $484,522,611.	6,000,000
5,000,000		Interest in $400,000,000 joint repurchase agreement 0.12%, dated 5/29/2015 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $400,009,333 on 6/5/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities with various maturities to 4/15/2025 and the market value of those underlying securities was $408,004,544.	5,000,000
40,000,000		Interest in $900,000,000 joint repurchase agreement 0.09%, dated 5/27/2015 under which Citigroup Global Markets, Inc. will repurchase securities provided as collateral for $900,015,750 on 6/3/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities and a U.S. Treasury security with various maturities to 7/25/2054 and the market value of those underlying securities was $922,377,002.	40,000,000
16,547,000		Interest in $3,500,000,000 joint repurchase agreement 0.09%, dated 5/29/2015 under which Credit Agricole CIB New York will repurchase securities provided as collateral for $3,500,026,250 on 6/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 5/15/2045 and the market value of those underlying securities was $3,570,026,786.	16,547,000

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Principal Amount			Value
		REPURCHASE AGREEMENTS—continued
$90,000,000		Interest in $500,000,000 joint repurchase agreement 0.11%, dated 5/29/2015 under which Mizuho Securities USA, Inc. will repurchase securities provided as collateral for $500,004,583 on 6/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities with various maturities to 6/20/2044 and the market value of those underlying securities was $510,769,425.	$90,000,000
80,000,000		Interest in $100,000,000 joint repurchase agreement 0.12%, dated 5/29/2015 under which Pershing LLC will repurchase securities provided as collateral for $100,001,000 on 6/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency and U.S. Treasury securities with various maturities to 2/16/2051 and the market value of those underlying securities was $102,155,053.	80,000,000
1,000,000	3	Interest in $100,000,000 joint repurchase agreement 0.11%, dated 5/13/2015 under which RBC Capital Markets, LLC will repurchase securities provided as collateral for $100,018,639 on 7/13/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities with various maturities to 5/20/2045 and the market value of those underlying securities was $102,385,973.	1,000,000
5,000,000	3	Interest in $360,000,000 joint repurchase agreement 0.12%, dated 4/10/2015 under which RBC Capital Markets, LLC will repurchase securities provided as collateral for $360,108,000 on 7/9/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities with various maturities to 5/20/2045 and the market value of those underlying securities was $367,276,382.	5,000,000
6,000,000		Interest in $500,000,000 joint repurchase agreement 0.09%, dated 5/28/2015 under which Societe Generale, New York will repurchase securities provided as collateral for $500,008,750 on 6/4/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities with various maturities to 5/1/2045 and the market value of those underlying securities was $510,336,850.	6,000,000
3,000,000	3	Interest in $250,000,000 joint repurchase agreement 0.13%, dated 3/30/2015 under which Wells Fargo Securities LLC will repurchase securities provided as collateral for $250,083,958 on 7/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities with various maturities to 10/3/2022 and the market value of those underlying securities was $255,058,121.	3,000,000

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Principal Amount			Value
		REPURCHASE AGREEMENTS—continued
$12,000,000	3	Interest in $450,000,000 joint repurchase agreement 0.13%, dated 5/13/2015 under which Wells Fargo Securities LLC will repurchase securities provided as collateral for $450,149,500 on 8/13/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities with various maturities to 6/1/2045 and the market value of those underlying securities was $460,642,958.	$12,000,000
		TOTAL REPURCHASE AGREEMENTS (AT COST)	289,547,000
		TOTAL INVESTMENTS—100.0% (AT AMORTIZED COST)4	498,540,050
		OTHER ASSETS AND LIABILITIES - NET—0.0%5	40,197
		TOTAL NET ASSETS—100%	$498,580,247

1	Floating rate notes with current rate and next reset date shown.
2	Discount rate(s) at time of purchase.
3	Although the repurchase date is more than seven days after the date of purchase, the Fund has the right to terminate the repurchase agreement at any time with seven-days' notice.
4	Also represents cost for federal tax purposes.
5	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.

Note: The categories of investments are shown as a percentage of total net assets at May 31, 2015.

Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below:

Level 1—quoted prices in active markets for identical securities.

Level 2—other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.). Also includes securities valued at amortized cost.

Level 3—significant unobservable inputs (including the Fund's own assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities.

As of May 31, 2015, all investments of the Fund are valued at amortized cost, which is considered a Level 2 input, in valuing the Fund's assets.

See Notes which are an integral part of the Financial Statements

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Financial Highlights

(For a Share Outstanding Throughout Each Period)

Year Ended May 31	2015	2014	2013	2012	2011
Net Asset Value, Beginning of Period	$1.00	$1.00	$1.00	$1.00	$1.00
Income From Investment Operations:
Net investment income	0.00001	0.0001	0.0001	0.0001	0.0001
Net realized gain on investments	0.00001	0.00001	0.00001	0.00001	0.00001
TOTAL FROM INVESTMENT OPERATIONS	0.00001	0.0001	0.0001	0.0001	0.0001
Less Distributions:
Distributions from net investment income	(0.0000)1	(0.0001)	(0.0001)	(0.0001)	(0.0001)
Distributions from net realized gain on investments	(0.0000)1	(0.0000)1	(0.0000)1	(0.0000)1	(0.0000)1
TOTAL DISTRIBUTIONS	(0.0000)1	(0.0001)	(0.0001)	(0.0001)	(0.0001)
Net Asset Value, End of Period	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return2	0.01%	0.01%	0.01%	0.01%	0.01%
Ratios to Average Net Assets:
Net expenses	0.09%	0.09%	0.18%	0.16%	0.23%
Net investment income	0.01%	0.01%	0.01%	0.01%	0.01%
Expense waiver/reimbursement3	0.98%	0.97%	0.88%	0.90%	0.84%
Supplemental Data:
Net assets, end of period (000 omitted)	$498,580	$2,470,320	$2,504,174	$2,557,022	$2,522,787

1	Represents less than $0.0001.
2	Based on net asset value.
3	This expense decrease is reflected in both the net expense and the net investment income ratios shown above.

See Notes which are an integral part of the Financial Statements

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Statement of Assets and Liabilities

May 31, 2015

Assets:
Investment in repurchase agreements	$289,547,000
Investment in securities	208,993,050
Total investment in securities, at amortized cost and fair value		$498,540,050
Cash		910
Income receivable		200,346
TOTAL ASSETS		498,741,306
Liabilities:
Payable for shares redeemed	15,233
Payable to adviser (Note 5)	42,663
Payable for transfer agent fee	45,169
Payable for Directors'/Trustees' fees (Note 5)	3,174
Payable for portfolio accounting fees	17,756
Payable for share registration costs	22,268
Payable for printing and postage	10,928
Accrued expenses (Note 5)	3,868
TOTAL LIABILITIES		161,059
Net assets for 498,548,564 shares outstanding		$498,580,247
Net Assets Consist of:
Paid-in capital		$498,548,564
Accumulated net realized gain on investments		31,352
Undistributed net investment income		331
TOTAL NET ASSETS		$498,580,247
Net Asset Value, Offering Price and Redemption Proceeds Per Share:
$498,580,247 ÷ 498,548,564 shares outstanding, $0.001 par value, 12,500,000,000 shares authorized		$1.00

See Notes which are an integral part of the Financial Statements

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Statement of Operations

Year Ended May 31, 2015

Investment Income:
Interest			$1,548,358
Expenses:
Investment adviser fee (Note 5)		$7,534,009
Administrative fee (Note 5)		1,179,144
Custodian fees		55,501
Transfer agent fee		1,627,096
Directors'/Trustees' fees (Note 5)		16,401
Auditing fees		19,600
Legal fees		10,551
Portfolio accounting fees		138,002
Distribution services fee (Note 5)		1,506,802
Other service fees (Note 2)		3,767,004
Share registration costs		52,858
Printing and postage		84,410
Taxes		173,550
Miscellaneous (Note 5)		19,089
TOTAL EXPENSES		16,184,017
Waivers and Reimbursement:
Waiver of investment adviser fee (Note 5)	$(7,534,009)
Waivers/reimbursement of other operating expenses (Notes 2 and 5)	(7,251,509)
TOTAL WAIVERS AND REIMBURSEMENT		(14,785,518)
Net expenses			1,398,499
Net investment income			149,859
Net realized gain on investments			31,897
Change in net assets resulting from operations			$181,756

See Notes which are an integral part of the Financial Statements

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Statement of Changes in Net Assets

Year Ended May 31	2015	2014
Increase (Decrease) in Net Assets
Operations:
Net investment income	$149,859	$249,730
Net realized gain on investments	31,897	2,463
CHANGE IN NET ASSETS RESULTING FROM OPERATIONS	181,756	252,193
Distributions to Shareholders:
Distributions from net investment income	(149,910)	(249,348)
Distributions from net realized gain on investments	(545)	(2,463)
CHANGE IN NET ASSETS RESULTING FROM DISTRIBUTIONS TO SHAREHOLDERS	(150,455)	(251,811)
Share Transactions:
Proceeds from sale of shares	1,513,857,991	1,941,111,954
Net asset value of shares issued to shareholders in payment of distributions declared	150,291	251,703
Cost of shares redeemed	(3,485,779,783)	(1,975,217,882)
CHANGE IN NET ASSETS RESULTING FROM SHARE TRANSACTIONS	(1,971,771,501)	(33,854,225)
Change in net assets	(1,971,740,200)	(33,853,843)
Net Assets:
Beginning of period	2,470,320,447	2,504,174,290
End of period (including undistributed net investment income of $331 and $382, respectively)	$498,580,247	$2,470,320,447

See Notes which are an integral part of the Financial Statements

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Notes to Financial Statements

May 31, 2015

1. ORGANIZATION

Cash Trust Series, Inc. (the “Corporation”) is registered under the Investment Company Act of 1940, as amended (the “Act”), as an open-end management investment company. The Corporation consists of four portfolios. The financial statements included herein are only those of Federated Government Cash Series (the “Fund”), a diversified portfolio. The financial statements of the other portfolios are presented separately. The assets of each portfolio are segregated and a shareholder's interest is limited to the portfolio in which shares are held. Each portfolio pays its own expenses. The investment objective of the Fund is current income consistent with stability of principal and liquidity.

2. SIGNIFICANT ACCOUNTING POLICIES

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. These policies are in conformity with U.S. generally accepted accounting principles (GAAP).

Investment Valuation

Securities are valued at amortized cost. Under the amortized cost valuation method, an investment is valued initially at its cost as determined in accordance with GAAP. The Fund then adjusts the amount of interest income accrued each day over the term of the investment to account for any difference between the initial cost of the investment and the amount payable at its maturity. If amortized cost is determined not to approximate fair value, the value of the portfolio securities will be determined in accordance with the procedures described below.

The Directors have ultimate responsibility for determining the fair value of investments. The Directors have appointed a valuation committee (“Valuation Committee”) comprised of officers of the Fund, Federated Investment Management Company (“Adviser”) and certain of the Adviser's affiliated companies to assist in determining fair value of securities and in overseeing the comparison of amortized cost to market-based value. The Directors have also authorized the use of pricing services recommended by the Valuation Committee to provide fair value evaluations of the current value of certain investments for purposes of monitoring the relationship of market-based value and amortized cost. The Valuation Committee employs various methods for reviewing third-party pricing-service evaluations including periodic reviews of third-party pricing services' policies, procedures and valuation methods (including key inputs and assumptions), and review of price challenges by the Adviser based on recent market activity. In the event that market quotations and price evaluations are not available for an investment, the Valuation Committee determines the fair value of the investment in accordance with procedures adopted by the Directors. The Directors periodically review and approve the fair valuations made by the Valuation Committee and any changes made to the procedures.

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Repurchase Agreements

The Fund may invest in repurchase agreements for short-term liquidity purposes. It is the policy of the Fund to require the other party to a repurchase agreement to transfer to the Fund's custodian or sub-custodian eligible securities or cash with a market value (after transaction costs) at least equal to the repurchase price to be paid under the repurchase agreement. The eligible securities are transferred to accounts with the custodian or sub-custodian in which the Fund holds a “securities entitlement” and exercises “control” as those terms are defined in the Uniform Commercial Code. The Fund has established procedures for monitoring the market value of the transferred securities and requiring the transfer of additional eligible securities if necessary to equal at least the repurchase price. These procedures also allow the other party to require securities to be transferred from the account to the extent that their market value exceeds the repurchase price or in exchange for other eligible securities of equivalent market value.

The insolvency of the other party or other failure to repurchase the securities may delay the disposition of the underlying securities or cause the Fund to receive less than the full repurchase price. Under the terms of the repurchase agreement, any amounts received by the Fund in excess of the repurchase price and related transaction costs must be remitted to the other party.

The Fund may enter into repurchase agreements in which eligible securities are transferred into joint trading accounts maintained by the custodian or sub-custodian for investment companies and other clients advised by the Fund's Adviser and its affiliates. The Fund will participate on a pro rata basis with the other investment companies and clients in its share of the securities transferred under such repurchase agreements and in its share of proceeds from any repurchase or other disposition of such securities.

Repurchase agreements are subject to Master Netting Agreements which are agreements between the Fund and its counterparties that provide for the net settlement of all transactions and collateral with the Fund, through a single payment, in the event of default or termination. Amounts presented on the Portfolio of Investments and Statement of Assets and Liabilities are not net settlement amounts but gross. As indicated above, the cash or securities to be repurchased, as shown on the Portfolio of Investments, exceeds the repurchase price to be paid under the agreement reducing the net settlement amount to zero.

Investment Income, Gains and Losses, Expenses and Distributions

Investment transactions are accounted for on a trade-date basis. Realized gains and losses from investment transactions are recorded on an identified-cost basis. Interest income and expenses are accrued daily. Distributions to shareholders are recorded on the ex-dividend date. Distributions of net investment income are declared daily and paid monthly.

For the year ended May 31, 2015, unaffiliated third parties waived $1,447,974 of transfer agent fees.

Dividends are declared separately for each class. No class has preferential dividend rights; differences in per share dividend rates are generally due to differences in separate class expenses.

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Other Service Fees

The Fund may pay other service fees up to 0.25% of the average daily net assets of the Fund's Shares to unaffiliated financial intermediaries or to Federated Shareholder Services Company (FSSC) for providing services to shareholders and maintaining shareholder accounts. Subject to the terms described in the Expense Limitation note, FSSC may voluntarily reimburse the Fund for other service fees. For the year ended May 31, 2015, unaffiliated third-party financial intermediaries waived $3,767,004 of other service fees. This wavier can be modified or terminated at any time.

Premium and Discount Amortization

All premiums and discounts are amortized/accreted using the effective-interest-rate method.

Federal Taxes

It is the Fund's policy to comply with the Subchapter M provision of the Internal Revenue Code and to distribute to shareholders each year substantially all of its income. Accordingly, no provision for federal income tax is necessary. As of and during the year ended May 31, 2015, the Fund did not have a liability for any uncertain tax positions. The Fund recognizes interest and penalties, if any, related to tax liabilities as income tax expense in the Statement of Operations. As of May 31, 2015, tax years 2012 through 2015 remain subject to examination by the Fund's major tax jurisdictions, which include the United States of America, the state of Maryland and the Commonwealth of Pennsylvania.

Other Taxes

As an open-end management investment company incorporated in the state of Maryland but domiciled in the Commonwealth of Pennsylvania, the Fund is subject to the Pennsylvania Franchise Tax. This franchise tax is assessed annually on the value of the Fund, as represented by average net assets for the tax year.

When-Issued and Delayed-Delivery Transactions

The Fund may engage in when-issued or delayed-delivery transactions. The Fund records when-issued securities on the trade date and maintains security positions such that sufficient liquid assets will be available to make payment for the securities purchased. Securities purchased on a when-issued or delayed-delivery basis are marked to market daily and begin earning interest on the settlement date. Losses may occur on these transactions due to changes in market conditions or the failure of counterparties to perform under the contract.

Other

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, expenses and revenues reported in the financial statements. Actual results could differ from those estimated. The Fund applies Investment Company accounting and reporting guidance.

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3. CAPITAL STOCK

The following table summarizes capital stock activity:

Year Ended May 31	2015	2014
Shares sold	1,513,857,991	1,941,111,954
Shares issued to shareholders in payment of distributions declared	150,291	251,703
Shares redeemed	(3,485,779,783)	(1,975,217,882)
NET CHANGE RESULTING FROM FUND SHARE TRANSACTIONS	(1,971,771,501)	(33,854,225)

4. FEDERAL TAX INFORMATION

The tax character of distributions as reported on the Statement of Changes in Net Assets for the years ended May 31, 2015 and 2014, was as follows:

	2015	2014
Ordinary income1	$150,455	$251,811

1 For tax purposes, short-term capital gain distributions are considered as ordinary income distributions.

As of May 31, 2015, the components of distributable earnings on a tax basis were as follows:

Undistributed ordinary income2	$24,201
Undistributed long-term capital gains	$7,482

2 For tax purposes, short-term capital gains are considered ordinary income in determining distributable earnings.

5. INVESTMENT ADVISER FEE AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Adviser Fee

The advisory agreement between the Fund and the Adviser provides for an annual fee equal to 0.50% of the Fund's average daily net assets. Subject to the terms described in the Expense Limitation note, the Adviser may voluntarily choose to waive any portion of its fee and/or reimburse certain operating expenses of the Fund. For the year ended May 31, 2015, the Adviser voluntarily waived its entire fee of $7,534,009 and voluntarily reimbursed $529,729 of other operating expenses.

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Administrative Fee

Federated Administrative Services (FAS), under the Administrative Services Agreement, provides the Fund with administrative personnel and services. For purposes of determining the appropriate rate breakpoint, “Investment Complex” is defined as all of the Federated Funds subject to a fee under the Administrative Services Agreement. The fee paid to FAS is based on the average daily net assets of the Investment Complex as specified below, plus certain out-of-pocket expenses:

Administrative Fee	Average Daily Net Assets of the Investment Complex
0.150%	on the first $5 billion
0.125%	on the next $5 billion
0.100%	on the next $10 billion
0.075%	on assets in excess of $20 billion

Subject to the terms described in the Expense Limitation note, FAS may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2015, the annualized fee paid to FAS was 0.078% of average daily net assets of the Fund.

Distribution Services Fee

The Fund has adopted a Distribution Plan (the “Plan”) pursuant to Rule 12b-1 under the Act. Under the terms of the Plan, the Fund will reimburse Federated Securities Corp. (FSC), the principal distributor, from the daily net assets of the Fund to finance activities intended to result in the sale of these shares. The Plan provides that the Fund may incur distribution expenses of up to 0.35% of average daily net assets, annually, to reimburse FSC. Subject to the terms described in the Expense Limitation note, FSC may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2015, FSC voluntarily waived its entire fee of $1,506,802. When FSC receives fees, it may pay some or all of them to financial intermediaries whose customers purchase shares.

Expense Limitation

Due to the possibility of changes in market conditions and other factors, there can be no assurance that the level of waivers/reimbursement/reduction of Fund expenses reflected in the financial highlights will be maintained in the future. However, the Adviser and certain of its affiliates (which may include FSC, FAS and FSSC), on their own initiative, have agreed to waive certain amounts of their respective fees and/or reimburse expenses. Total annual fund operating expenses (as shown in the financial highlights, excluding extraordinary expenses and proxy-related expenses paid by the Fund, if any) paid by the Fund (after the voluntary waivers and/or reimbursements) will not exceed 1.05% (the “Fee Limit”), up to but not including the later of (the “Termination Date”): (a) August 1, 2016; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its applicable affiliates currently do not anticipate terminating or increasing these arrangements prior to the Termination Date, these arrangements may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Directors.

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Interfund Transactions

During the year ended May 31, 2015, the Fund engaged in sale transactions with funds that have a common investment adviser (or affiliated investment advisers), common Directors/Trustees and/or common Officers. These sale transactions complied with Rule 17a-7 under the Act and amounted to $203,817,274.

General

Certain Officers and Directors of the Fund are Officers and Directors or Trustees of certain of the above companies. To efficiently facilitate payment, Directors'/Trustees' fees and certain expenses related to conducting meetings of the Directors/Trustees and other miscellaneous expenses are paid by an affiliate of the Adviser which in due course are reimbursed by the Fund. Such expenses may be included in Accrued and Miscellaneous Expenses on the Statement of Assets and Liabilities and Statement of Operations, respectively.

6. LINE OF CREDIT

The Fund participates in a $100,000,000 unsecured, uncommitted revolving line of credit (LOC) agreement with PNC Bank. The LOC was made available for extraordinary or emergency purposes, primarily for financing redemption payments. Borrowings are charged interest at a rate offered to the Fund by PNC Bank at the time of the borrowing. As of May 31, 2015, there were no outstanding loans. During the year ended May 31, 2015, the Fund did not utilize the LOC.

7. INTERFUND LENDING

Pursuant to an Exemptive Order issued by the Securities and Exchange Commission (SEC), the Fund, along with other funds advised by subsidiaries of Federated Investors, Inc., may participate in an interfund lending program. This program provides an alternative credit facility allowing the Fund to borrow from other participating affiliated funds. As of May 31, 2015, there were no outstanding loans. During the year ended May 31, 2015, the program was not utilized.

8. regulatory matters

On July 23, 2014, the Securities and Exchange Commission voted to amend the rules under the Act which currently govern the operations of the Fund. A significant change resulting from these amendments will be a requirement that institutional prime funds (i.e. not government or retail as defined in the amendments), transact fund shares based on a market-based Net Asset Value (NAV). This change does not impact government money market funds, and because it is anticipated that the Fund will constitute a government money market fund under the new rules, the Fund will be permitted to continue transacting fund shares at an NAV calculated using the amortized cost valuation method. Among additional disclosure and other requirements, the amendments also will permit a money market fund, or, in certain circumstances, require a money market fund (other than a government money market fund, like the Fund, which satisfies the requirements of the amended rules) to impose liquidity fees on redemptions, and permit a money market fund to limit (or gate) redemptions for up to 10 business days in any 90-day period. The amendments have staggered compliance dates. Compliance with a majority of these amendments will be required on October 14, 2016, two years after the effective date for the rule amendments. The degree to which a money market fund will be impacted by the rule amendments will depend upon the type of fund and type of investors (retail or institutional). At this time, management is evaluating the implications of these amendments and their impact to the Fund's operations, financial statements and accompanying notes.

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9. SUBSEQUENT EVENTS

On June 3, 2015, the Fund filed a supplement to its current Prospectus notifying shareholders that the Directors have approved a proposed Agreement and Plan of Reorganization (Reorganization) pursuant to which Federated Government Obligations Fund would acquire all or substantially all of the assets of the Fund in complete liquidation and termination of the Fund. Information statements will be sent to shareholders explaining the Reorganization. The Reorganization is expected to occur in the fourth quarter of 2015.

Management has evaluated subsequent events through the date the financial statements were issued and determined that no additional events occurred that require disclosure.

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Report of Independent Registered Public Accounting Firm

TO THE BOARD OF directors OF Cash TRUST SERIES, INC. AND SHAREHOLDERS Of Federated government cash Series:

We have audited the accompanying statement of assets and liabilities of Federated Government Cash Series (the “Fund”) (one of the portfolios constituting Cash Trust Series, Inc.), including the portfolio of investments, as of May 31, 2015, and the related statement of operations for the year then ended, the statement of changes in net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended. These financial statements and financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

We conducted our audits in accordance with standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. We were not engaged to perform an audit of the Fund's internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements and financial highlights, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of May 31, 2015, by correspondence with the custodian and others. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Federated Government Cash Series, a portfolio of Cash Trust Series, Inc., at May 31, 2015, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended, in conformity with U.S. generally accepted accounting principles.

Boston, Massachusetts
July 23, 2015

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Shareholder Expense Example (unaudited)

As a shareholder of the Fund, you incur ongoing costs, including management fees and to the extent applicable, distribution (12b-1) fees and/or other service fees and other Fund expenses. This Example is intended to help you to understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. It is based on an investment of $1,000 invested at the beginning of the period and held for the entire period from December 1, 2014 to May 31, 2015.

ACTUAL EXPENSES

The first section of the table below provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you incurred over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses attributable to your investment during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second section of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. Thus, you should not use the hypothetical account values and expenses to estimate the actual ending account balance or your expenses for the period. Rather, these figures are required to be provided to enable you to compare the ongoing costs of investing in the Fund with other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

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Please note that the expenses shown in the table are meant to highlight your ongoing costs only. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

	Beginning Account Value 12/1/2014	Ending Account Value 5/31/2015	Expenses Paid During Period1,2
Actual	$1,000	$1,000.10	$0.60
Hypothetical (assuming a 5% return before expenses)	$1,000	$1,024.33	$0.61

1

Expenses are equal to the Fund's annualized net expense ratio of 0.12%, multiplied by the average account value over the period, multiplied by 182/365 (to reflect the one-half-year period).

2

Actual and Hypothetical expenses paid during the period utilizing the Fund's current Fee Limit of 1.05% (as reflected in the Notes to Financial Statements, Note 5 under Expense Limitation), multiplied by the average account value over the period, multiplied by 182/365 (to reflect expenses paid as if they had been in effect throughout the most recent one-half-year period) would be $5.24 and $5.29, respectively.

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Board of Directors and Corporation Officers

The Board of Directors is responsible for managing the Corporation's business affairs and for exercising all the Corporation's powers except those reserved for the shareholders. The following tables give information about each Director and the senior officers of the Fund. Where required, the tables separately list Directors who are “interested persons” of the Fund (i.e., “Interested” Directors) and those who are not (i.e., “Independent” Directors). Unless otherwise noted, the address of each person listed is Federated Investors Tower, 1001 Liberty Avenue, Pittsburgh, PA 15222. The address of all Independent Directors listed is 4000 Ericsson Drive, Warrendale, PA 15086-7561; Attention: Mutual Fund Board. As of December 31, 2014, the Corporation comprised four portfolio(s), and the Federated Fund Family consisted of 40 investment companies (comprising 131 portfolios). Unless otherwise noted, each Officer is elected annually. Unless otherwise noted, each Director oversees all portfolios in the Federated Fund Family and serves for an indefinite term. The Fund's Statement of Additional Information includes additional information about Corporation Directors and is available, without charge and upon request, by calling 1-800-341-7400.

Interested DIRECTORS Background

Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years, Other Directorships Held and Previous Position(s)
John F. Donahue* Birth Date: July 28, 1924 Director Indefinite Term Began serving: May 1989	Principal Occupations: Director or Trustee of the Federated Fund Family; Chairman and Director, Federated Investors, Inc.; Chairman of the Federated Fund Family's Executive Committee. Previous Positions: Chairman of the Federated Fund Family; Trustee, Federated Investment Management Company; Chairman and Director, Federated Investment Counseling.

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Name Birth Date Positions Held with Corporation Date Service Began

Principal Occupation(s) for Past Five Years, Other Directorships Held and Previous Position(s)

J. Christopher Donahue* Birth Date: April 11, 1949 President and Director Indefinite Term Began serving: May 1989

Principal Occupations: Principal Executive Officer and President of certain of the Funds in the Federated Fund Family; Director or Trustee of the Funds in the Federated Fund Family; President, Chief Executive Officer and Director, Federated Investors, Inc.; Chairman and Trustee, Federated Investment Management Company; Trustee, Federated Investment Counseling; Chairman and Director, Federated Global Investment Management Corp.; Chairman, Federated Equity Management Company of Pennsylvania and Passport Research, Ltd. (investment advisory subsidiary of Federated); Trustee, Federated Shareholder Services Company; Director, Federated Services Company. Previous Positions: President, Federated Investment Counseling; President and Chief Executive Officer, Federated Investment Management Company, Federated Global Investment Management Corp. and Passport Research, Ltd.

* Family relationships and reasons for “interested” status: John F. Donahue is the father of J. Christopher Donahue; both are “interested” due to their beneficial ownership of shares of Federated Investors, Inc. and the positions they hold with Federated and its subsidiaries.

INDEPENDENT DIRECTORS Background

Name Birth Date Positions Held with Corporation Date Service Began

Principal Occupation(s) for Past Five Years, Other Directorships Held, Previous Position(s) and Qualifications

John T. Collins Birth Date: January 24, 1947 Director Indefinite Term Began serving: October 2013

Principal Occupations: Director or Trustee of the Federated Fund Family; Chairman and CEO, The Collins Group, Inc. (a private equity firm). Other Directorships Held: Director, Chair of the Compensation Committee, Audit Committee member, KLX Corp. Qualifications: Mr. Collins has served in several business and financial management roles and directorship positions throughout his career. Mr. Collins serves as Chairman Emeriti, Bentley University. Mr. Collins previously served as Director, FleetBoston Financial Corp.; Director and Audit Committee Member, Bank of America Corp. and Director, Beth Israel Deaconess Medical Center (Harvard University Affiliate Hospital).

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Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years, Other Directorships Held, Previous Position(s) and Qualifications
Maureen Lally-Green Birth Date: July 5, 1949 Director Indefinite Term Began serving: August 2009	Principal Occupations: Director or Trustee of the Federated Fund Family; Adjunct Professor of Law, Duquesne University School of Law. Other Directorships Held: Director, CONSOL Energy Inc. Qualifications: Judge Lally-Green has served in various legal and business roles and directorship positions throughout her career. Judge Lally-Green previously served as: Associate General Secretary, Diocese of Pittsburgh; Professor of Law, Duquesne University School of Law and was a member of the Superior Court of Pennsylvania. Judge Lally-Green also holds the positions of: Member, Pennsylvania State Board of Education; Director, Saint Vincent College; Director and Chair, UPMC Mercy Hospital; Regent, St. Vincent Seminary; Director, Epilepsy Foundation of Western and Central Pennsylvania; Director, Our Campaign for the Church Alive!, Inc.; Director, Pennsylvania Bar Institute; and Director, Catholic High Schools of the Diocese of Pittsburgh, Inc. Judge Lally-Green has held the positions of: Director, Auberle; Director, Ireland Institute of Pittsburgh; Director, Saint Thomas More Society; and Director Cardinal Wuerl Catholic High School.
Peter E. Madden Birth Date: March 16, 1942 Director Indefinite Term Began serving: August 1991	Principal Occupation: Director or Trustee, and Chair of the Board of Directors or Trustees, of the Federated Fund Family; Retired. Other Directorships Held: None. Qualifications: Mr. Madden has served in several business management, mutual fund services and directorship positions throughout his career. Mr. Madden previously served as President, Chief Operating Officer and Director, State Street Bank and Trust Company (custodian bank) and State Street Corporation (financial services). He was Director, VISA USA and VISA International and Chairman and Director, Massachusetts Bankers Association. Mr. Madden served as Director, Depository Trust Corporation and Director, The Boston Stock Exchange. Mr. Madden also served as a Representative to the Commonwealth of Massachusetts General Court.
Charles F. Mansfield, Jr. Birth Date: April 10, 1945 Director Indefinite Term Began serving: January 1999	Principal Occupations: Director or Trustee of the Federated Fund Family; Management Consultant. Other Directorships Held: None. Qualifications: Mr. Mansfield has served in several banking, business management and educational roles and directorship positions throughout his career. Mr. Mansfield previously served as Chief Executive Officer, PBTC International Bank; Partner, Arthur Young & Company (now Ernst & Young LLP); Chief Financial Officer of Retail Banking Sector, Chase Manhattan Bank; Senior Vice President, HSBC Bank USA (formerly, Marine Midland Bank); Vice President, Citibank; Assistant Professor of Banking and Finance, Frank G. Zarb School of Business, Hofstra University; Executive Vice President DVC Group, Inc. (marketing, communications and technology).

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Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years, Other Directorships Held, Previous Position(s) and Qualifications
Thomas M. O'Neill Birth Date: June 14, 1951 Director Indefinite Term Began serving: October 2006	Principal Occupations: Director or Trustee, Vice Chair of the Audit Committee of the Federated Fund Family; Sole Proprietor, Navigator Management Company (investment and strategic consulting). Other Directorships Held: None. Qualifications: Mr. O'Neill has served in several business, mutual fund and financial management roles and directorship positions throughout his career. Mr. O'Neill serves as Director, Medicines for Humanity and Director, The Golisano Children's Museum of Naples, Florida. Mr. O'Neill previously served as Chief Executive Officer and President, Managing Director and Chief Investment Officer, Fleet Investment Advisors; President and Chief Executive Officer, Aeltus Investment Management, Inc.; General Partner, Hellman, Jordan Management Co., Boston, MA; Chief Investment Officer, The Putnam Companies, Boston, MA; Credit Analyst and Lending Officer, Fleet Bank; Director and Consultant, EZE Castle Software (investment order management software); and Director, Midway Pacific (lumber).
P. Jerome Richey Birth Date: February 23, 1949 Director Indefinite Term Began serving: October 2013	Principal Occupations: Director or Trustee of the Federated Fund Family; Management Consultant. Other Directorships Held: None. Qualifications: Mr. Richey has served in several business and legal management roles and directorship positions throughout his career. Mr. Richey most recently held the positions of Senior Vice Chancellor and Chief Legal Officer, University of Pittsburgh. Mr. Richey serves as Board Member, Epilepsy Foundation of Western Pennsylvania and Board member, World Affairs Council of Pittsburgh. Mr. Richey previously served as Chief Legal Officer and Executive Vice President, CONSOL Energy Inc. and Shareholder, Buchanan Ingersoll & Rooney PC (a law firm).
John S. Walsh Birth Date: November 28, 1957 Director Indefinite Term Began serving: January 1999	Principal Occupations: Director or Trustee, Chair of the Audit Committee of the Federated Fund Family; President and Director, Heat Wagon, Inc. (manufacturer of construction temporary heaters); President and Director, Manufacturers Products, Inc. (distributor of portable construction heaters); President, Portable Heater Parts, a division of Manufacturers Products, Inc. Other Directorships Held: None. Qualifications: Mr. Walsh has served in several business management roles and directorship positions throughout his career. Mr. Walsh previously served as Vice President, Walsh & Kelly, Inc. (paving contractors).

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OFFICERS

Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years and Previous Position(s)
John W. McGonigle Birth Date: October 26, 1938 EXECUTIVE VICE PRESIDENT AND SECRETARY Officer since: May 1989	Principal Occupations: Executive Vice President and Secretary of the Federated Fund Family; Vice Chairman, Executive Vice President, Secretary and Director, Federated Investors, Inc. Previous Positions: Trustee, Federated Investment Management Company and Federated Investment Counseling; Director, Federated Global Investment Management Corp., Federated Services Company and Federated Securities Corp.
Lori A. Hensler Birth Date: January 6, 1967 TREASURER Officer since: April 2013	Principal Occupations: Principal Financial Officer and Treasurer of the Federated Fund Family; Senior Vice President, Federated Administrative Services; Financial and Operations Principal for Federated Securities Corp. and Edgewood Services, Inc.; and Assistant Treasurer, Federated Investors Trust Company. Ms. Hensler has received the Certified Public Accountant designation. Previous Positions: Controller of Federated Investors, Inc.; Senior Vice President and Assistant Treasurer, Federated Investors Management Company; Treasurer, Federated Investors Trust Company; Assistant Treasurer, Federated Administrative Services, Federated Administrative Services, Inc., Federated Securities Corp., Edgewood Services, Inc., Federated Advisory Services Company, Federated Equity Management Company of Pennsylvania, Federated Global Investment Management Corp., Federated Investment Counseling, Federated Investment Management Company, Passport Research, Ltd., and Federated MDTA, LLC; Financial and Operations Principal for Federated Securities Corp., Edgewood Services, Inc. and Southpointe Distribution Services, Inc.
Peter J. Germain Birth Date: September 3, 1959 CHIEF LEGAL OFFICER Officer since: January 2005	Principal Occupations: Mr. Germain is Chief Legal Officer of the Federated Fund Family. He is General Counsel and Vice President, Federated Investors, Inc.; President, Federated Administrative Services and Federated Administrative Services, Inc.; Vice President, Federated Securities Corp.; Secretary, Federated Private Asset Management, Inc.; and Secretary, Retirement Plan Service Company of America. Mr. Germain joined Federated in 1984 and is a member of the Pennsylvania Bar Association. Previous Positions: Deputy General Counsel, Special Counsel, Managing Director of Mutual Fund Services, Federated Investors, Inc.; Senior Vice President, Federated Services Company; and Senior Corporate Counsel, Federated Investors, Inc.
Richard B. Fisher Birth Date: May 17, 1923 VICE CHAIRMAN Officer since: August 2002	Principal Occupations: Vice Chairman or Vice President of some of the Funds in the Federated Fund Family; Vice Chairman, Federated Investors, Inc.; Chairman, Federated Securities Corp. Previous Positions: President and Director or Trustee of some of the Funds in the Federated Fund Family; Executive Vice President, Federated Investors, Inc.; Director and Chief Executive Officer, Federated Securities Corp.

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Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years and Previous Position(s)
Brian P. Bouda Birth Date: February 28, 1947 CHIEF COMPLIANCE OFFICER AND SENIOR VICE PRESIDENT Officer since: August 2004; Retiring July 29, 2015	Principal Occupations: Senior Vice President and Chief Compliance Officer of the Federated Fund Family; Vice President and Chief Compliance Officer of Federated Investors, Inc. and Chief Compliance Officer of certain of its subsidiaries. Mr. Bouda joined Federated in 1999 and is a member of the American Bar Association and the State Bar Association of Wisconsin. Previous Positions: Served in Senior Management positions with a large regional banking organization.
Stephen Van Meter Birth Date: June 5, 1975 CHIEF COMPLIANCE OFFICER AND SENIOR VICE PRESIDENT Officer since: Effective July 30, 2015	Principal Occupations: Senior Vice President and Chief Compliance Officer of the Federated Fund Family; Vice President and Chief Compliance Officer of Federated Investors, Inc. and Chief Compliance Officer of certain of its subsidiaries. Mr. Van Meter joined Federated in October 2011. He holds FINRA licenses under Series 3, 7, 24 and 66. Previous Positions: Mr. Van Meter previously held the position of Compliance Operating Officer, Federated Investors, Inc. Prior to joining Federated, Mr. Van Meter served at the United States Securities and Exchange Commission in the positions of Senior Counsel, Office of Chief Counsel, Division of Investment Management and Senior Counsel, Division of Enforcement.
Deborah A. Cunningham Birth Date: September 15, 1959 CHIEF INVESTMENT OFFICER Officer since: May 2004 Portfolio Manager since: January 1994	Principal Occupations: Deborah A. Cunningham has been the Fund's Portfolio Manager since January 1994. Ms. Cunningham was named Chief Investment Officer of Federated's money market products in 2004. She joined Federated in 1981 and has been a Senior Portfolio Manager since 1997 and an Executive Vice President of the Fund's Adviser since 2009. Ms. Cunningham has received the Chartered Financial Analyst designation and holds an M.S.B.A. in Finance from Robert Morris College.
Susan R. Hill Birth Date: June 20, 1963 VICE PRESIDENT Officer since: June 2012 Portfolio Manager since: January 1994	Principal Occupations: Susan R. Hill has been the Fund's Portfolio Manager since January 1994. She is Vice President of the Corporation with respect to the Fund. Ms. Hill joined Federated in 1990 and has been a Senior Portfolio Manager since 2003 and a Senior Vice President of the Fund's Adviser since 2005. Ms. Hill was a Portfolio Manager from 1994 until 2003 and served as Vice President of the Fund's Adviser from 1997 until 2004 and an Assistant Vice President of the Fund's Adviser from 1994 until 1997. Ms. Hill has received the Chartered Financial Analyst designation and holds an M.S. in Industrial Administration from Carnegie Mellon University.

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Evaluation and Approval of Advisory Contract–May 2015

Federated Government Cash Series (the “Fund”)

Following a review and recommendation of approval by the Fund's independent directors, the Fund's Board reviewed and approved at its May 2015 meetings the Fund's investment advisory contract for an additional one-year term. The Board's decision regarding the contract reflects the exercise of its business judgment on whether to continue the existing arrangements.

In this connection, the Federated Funds' Board had previously appointed a Senior Officer, whose duties include specified responsibilities relating to the process by which advisory fees are to be charged to a Federated fund. The Senior Officer has the authority to retain consultants, experts, or staff as may be reasonably necessary to assist in the performance of his duties, reports directly to the Board, and may be terminated only with the approval of a majority of the independent members of the Board. The Senior Officer prepared and furnished to the Board an independent, written evaluation that covered topics discussed below (the “Evaluation”). The Board considered that Evaluation, along with other information, in deciding to approve the advisory contract.

The Board is also familiar with and considered judicial decisions concerning allegedly excessive investment advisory fees, which have indicated that the following factors may be relevant to an Adviser's fiduciary duty with respect to its receipt of compensation from a fund: the nature and quality of the services provided by the Adviser to a fund and its shareholders, including the performance and expenses of the fund and of comparable funds; the Adviser's cost of providing the services, including the profitability to the Adviser of providing advisory services to a fund; the extent to which the Adviser may realize “economies of scale” as a fund grows larger and, if such economies of scale exist, whether they have been shared with a fund and its shareholders or the family of funds; any “fall-out financial benefits” that accrue to the Adviser because of its relationship with a fund (including research services received from brokers that execute fund trades and any fees paid to affiliates of the Adviser for services rendered to a fund); comparative fee structures, including a comparison of fees paid to the Adviser with those paid by similar funds; and the extent of care, conscientiousness and independence with which the Board members perform their duties and their expertise, including whether they are fully informed about all facts the Board deems relevant to its consideration of the Adviser's services and fees. The Board noted that SEC disclosure requirements regarding the basis for the Board's approval of the Fund's advisory contract generally track the factors listed above. Consistent with these judicial decisions and SEC disclosure requirements, the Board also considered management fees charged to institutional and other clients of the Adviser for what might be viewed as like services. The Board was aware of these factors and was guided by them in its review of the Fund's advisory contract to the extent it considered them to be appropriate and relevant, as discussed further below.

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The Board considered and weighed these circumstances in light of its substantial accumulated experience in governing the Fund and working with Federated on matters relating to the Federated funds, and was assisted in its deliberations by independent legal counsel. Throughout the year, and in connection with its May meetings, the Board requested and received substantial and detailed information about the Fund and the Federated organization that was in addition to the extensive materials that comprise and accompany the Senior Officer's Evaluation. Federated provided much of this information at each regular meeting of the Board, and furnished additional substantial information in connection with the May meeting at which the Board's formal review of the advisory contract occurred. At this May meeting, senior management of the Adviser also met with the independent directors and their counsel to discuss the materials presented and any other matters thought relevant by the Adviser or the directors. Between regularly scheduled meetings, the Board also received information on particular matters as the need arose. Thus, the Board's consideration of the advisory contract included review of the Senior Officer's Evaluation, accompanying data and additional information covering such matters as: the Adviser's investment philosophy, revenue, profitability, personnel and processes; investment and operating strategies; the Fund's short- and long-term performance (in absolute terms, both on a gross basis and net of expenses, as well as in relationship to its particular investment program and certain competitor or “peer group” funds and/or other benchmarks, as appropriate), and comments on the reasons for performance; the Fund's investment objectives; the Fund's expenses (including the advisory fee itself and the overall expense structure of the Fund, both in absolute terms and relative to similar and/or competing funds, with due regard for contractual or voluntary expense limitations); the use and allocation of brokerage commissions derived from trading the Fund's portfolio securities (if any); and the nature, quality and extent of the advisory and other services provided to the Fund by the Adviser and its affiliates. The Board also considered the preferences and expectations of Fund shareholders; the entrepreneurial risk assumed by the Adviser in sponsoring the funds; the continuing state of competition in the mutual fund industry and market practices; the range of comparable fees for similar funds in the mutual fund industry; the Fund's relationship to the Federated family of funds which include a comprehensive array of funds with different investment objectives, policies and strategies which are available for exchange without the incurrence of additional sales charges; compliance and audit reports concerning the Federated funds and the Federated companies that service them (including communications from regulatory agencies), as well as Federated's responses to any issues raised therein; and relevant developments in the mutual fund industry and how the Federated funds and/or Federated are responding to them. The Board's evaluation process is evolutionary. The criteria considered and the emphasis placed on relevant criteria change in recognition of changing circumstances in the mutual fund marketplace.

While mindful that courts have cautioned against giving such comparisons too much weight, the Board has found the use of comparisons of the Fund's fees and expenses to other mutual funds with comparable investment programs to be relevant. In this regard, the Board was presented with, and considered,

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information regarding the contractual advisory fee rates, net advisory fee rates and total expense ratios relative to a fund's peers. The Board focused on comparisons with other similar mutual funds more heavily than non-mutual fund products or services because it is believed that they are more relevant. For example, other mutual funds are the products most like the Fund, they are readily available to Fund shareholders as alternative investment vehicles, and they are the type of investment vehicle in fact chosen and maintained by the Fund's investors. The range of their fees and expenses therefore appears to be a relevant indicator of what consumers have found to be reasonable in the precise marketplace in which the Fund competes.

It was noted in the materials for the Board meeting that for the period covered by the Evaluation, the Fund's investment advisory fee was waived in its entirety. The Board reviewed the contractual advisory fee rate, net advisory fee rate and other expenses of the Fund with the Adviser and noted the position of the Fund's fee rates relative to its peers. In this regard, the Board noted that the contractual advisory fee rate was above the median of the relevant peer group, but the Board noted that the investment advisory fee was waived in its entirety and that the overall expense structure of the Fund remained competitive.

By contrast, the Senior Officer has reviewed Federated's fees for providing advisory services to products outside the Federated family of funds (e.g., institutional and separate accounts and sub-adviser services). He concluded that mutual funds and institutional accounts are inherently different products. Those differences include, but are not limited to, different types of targeted investors; being subject to different laws and regulations; different legal structures; different average account sizes and portfolio management techniques made necessary by different cash flows and different associated costs; and the time spent by portfolio managers and their teams, funds financial services, legal, compliance and risk management in reviewing securities pricing, addressing different administrative responsibilities, addressing different degrees of risk associated with management and a variety of different costs. The Senior Officer did not consider these fee schedules to be determinative in judging the appropriateness of mutual fund advisory fees.

The Fund's ability to deliver competitive performance when compared to its peer group was also deemed to be relevant by the Board as a useful indicator of how the Adviser is executing the Fund's investment program, which in turn was one of the Board's considerations in reaching a conclusion that the nature, extent, and quality of the Adviser's investment management services were such as to warrant continuation of the advisory contract.

The Senior Officer reviewed information compiled by Federated, using data supplied by independent fund ranking organizations, regarding the performance of, and fees charged by, other mutual funds, noting his view that comparisons to fund peer groups may be helpful, though not conclusive, in judging the reasonableness of the proposed fees. The Board considered, in evaluating such comparisons, that in some cases individual funds may exhibit significant and unique differences in their objectives and management techniques when compared to other funds within an industry peer group.

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The Fund's performance was above the median of the relevant peer group for the one-year period covered by the Evaluation.

The Board also received financial information about Federated, including information regarding the compensation and benefits Federated derived from its relationships with the Federated funds. This information covered not only the fees under the advisory contracts, but also fees received by Federated's subsidiaries for providing other services to the Federated funds under separate contracts (e.g., for serving as the Federated funds' administrator). The information also detailed any indirect benefit Federated may derive from its receipt of research services from brokers who execute Federated fund trades. In addition, the Board considered the fact that, in order for a fund to be competitive in the marketplace, Federated and its affiliates frequently waived fees and/or reimbursed expenses and have disclosed to fund investors and/or indicated to the Board their intention to do so in the future, where appropriate. Moreover, the Board receives regular reporting as to the institution, adjustment or elimination of these voluntary waivers.

In addition, over the past two years, following discussions regarding the Senior Officer's recommendations, Federated made meaningful reductions to the contractual advisory fees for several Funds. In May 2014, the Senior Officer recommended that Federated review the fee structures of its money market funds to determine whether it would be appropriate to consider alternative pricing structures. Federated has combined that review with its consideration of the re-structuring of its money market fund product line in response to the recently adopted amendments to Rule 2a-7 under the Investment Company Act of 1940, as amended (the “1940 Act”).

At the Board meeting in May 2015, following previous recommendations of the Senior Officer, Federated proposed, and the Board approved, reductions in the contractual advisory fees of certain other Funds.

Federated furnished information, requested by the Senior Officer, that reported revenues on a fund-by-fund basis and made estimates of the allocation of expenses on a fund-by-fund basis, using allocation methodologies specified by the Senior Officer. The Senior Officer noted that, while these cost allocation reports apply consistent allocation processes, the inherent difficulties in allocating costs continues to cause the Senior Officer to question the precision of the process and to conclude that such reports may be unreliable, since a single change in an allocation estimate may dramatically alter the resulting estimate of cost and/or profitability of a fund and may produce unintended consequences. The allocation information, including the Senior Officer's view that fund-by-fund estimations may be unreliable, was considered in the analysis by the Board.

The Board and the Senior Officer also reviewed information compiled by Federated comparing profitability information for Federated to other publicly held fund management companies. In this regard, the Senior Officer concluded that Federated's profit margins did not appear to be excessive. The Senior Officer also noted that Federated appeared financially sound, with the resources to fulfill its obligations under its contracts with the Funds.

Annual Shareholder Report

29

The Senior Officer's Evaluation also discussed the notion of possible realization of “economies of scale” as a fund grows larger. The Board considered in this regard that the Adviser has made significant and long-term investments in areas that support all of the Federated family of funds, such as personnel and processes for the portfolio management, shareholder services, compliance, internal audit, and risk management functions; and systems technology; and that the benefits of these efforts (as well as any economies of scale, should they exist) were likely to be enjoyed by the fund family as a whole. Federated, as it does throughout the year, and again in connection with the Board's review, furnished information relative to revenue sharing or adviser paid fees. Federated and the Senior Officer noted that this information should be viewed to determine if there was an incentive to either not apply breakpoints or to apply breakpoints at higher levels and should not be viewed to determining the appropriateness of advisory fees, because it would represent marketing and distribution expenses. Finally, the Board also noted the absence of any applicable regulatory or industry guidelines on this subject, which (as discussed in the Senior Officer's Evaluation) is compounded by the lack of any common industry practice or general pattern with respect to structuring fund advisory fees with “breakpoints” that serve to reduce the fee as the fund attains a certain size.

The Senior Officer noted that, subject to the comments and recommendations made within his Evaluation, his observations and the information accompanying the Evaluation supported a finding by the Board that the management fees for each of the funds were reasonable. Under these circumstances, no objection was raised to the continuation of, the Fund's advisory contract.

In its decision to continue an existing investment advisory contract, the Board was mindful of the potential disruptions of the Fund's operations and various risks, uncertainties and other effects that could occur as a result of a decision to terminate or not renew an advisory contract. In particular, the Board recognized that many shareholders have invested in the Fund on the strength of the Adviser's industry standing and reputation and with the expectation that the Adviser will have a continuing role in providing advisory services to the Fund. Thus, the Board's approval of the advisory contract reflected the fact that it is the shareholders who have effectively selected the Adviser by virtue of having invested in the Fund. The Board concluded that, in light of the factors discussed above, including the nature, quality and scope of the services provided to the Fund by the Adviser and its affiliates, continuation of the advisory contract was appropriate.

The Board based its decision to approve the advisory contract on the totality of the circumstances and relevant factors and with a view to past and future long-term considerations. Not all of the factors and considerations identified above were necessarily relevant to the Fund, nor did the Board consider any one of them to be determinative. With respect to the factors that were relevant, the Board's decision to approve the contract reflects its determination that Federated's performance and actions provided a satisfactory basis to support the decision to continue the existing arrangements.

Annual Shareholder Report

30

Voting Proxies on Fund Portfolio Securities

A description of the policies and procedures that the Fund uses to determine how to vote proxies, if any, relating to securities held in the Fund's portfolio is available, without charge and upon request, by calling 1-800-341-7400. A report on “Form N-PX” of how the Fund voted any such proxies during the most recent 12-month period ended June 30 is available via the Proxy Voting Record (Form N-PX) link associated with the Fund and share class name at www.FederatedInvestors.com/FundInformation. Form N-PX filings are also available at the SEC's website at www.sec.gov.

Quarterly Portfolio Schedule

The Fund files with the SEC a complete schedule of its portfolio holdings, as of the close of the first and third quarters of its fiscal year, on “Form N-Q.” These filings are available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, DC. (Call 1-800-SEC-0330 for information on the operation of the Public Reference Room.) You may also access this information via the link to the Fund and share class name at www.FederatedInvestors.com/FundInformation.

Annual Shareholder Report

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Notes

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Mutual funds are not bank deposits or obligations, are not guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency. Investment in mutual funds involves investment risk, including the possible loss of principal. Although money market funds seek to maintain a stable net asset value of $1.00 per share, there is no assurance that they will be able to do so.

This Report is authorized for distribution to prospective investors only when preceded or accompanied by the Fund's Prospectus, which contains facts concerning its objective and policies, management fees, expenses and other information.

Federated Government Cash Series
Federated Investors Funds
4000 Ericsson Drive
Warrendale, PA 15086-7561

Contact us at FederatedInvestors.com
or call 1-800-341-7400.

Federated Securities Corp., Distributor

CUSIP 147551204

28564 (7/15)

Federated is a registered trademark of Federated Investors, Inc.
2015 ©Federated Investors, Inc.

Annual Shareholder Report

May 31, 2015

Ticker CMSXX

Federated Municipal Cash Series

A Portfolio of Cash Trust Series, Inc.

Not FDIC Insured
May Lose Value

No Bank Guarantee

CONTENTS

Portfolio of Investments Summary Tables	1
Portfolio of Investments	2
Financial Highlights	8
Statement of Assets and Liabilities	9
Statement of Operations	10
Statement of Changes in Net Assets	11
Notes to Financial Statements	12
Report of Independent Registered Public Accounting Firm	18
Shareholder Expense Example	19
Board of Directors and Corporation Officers	20
Evaluation and Approval of Advisory Contract	26
Voting Proxies on Fund Portfolio Securities	32
Quarterly Portfolio Schedule	32

Portfolio of Investments Summary Tables (unaudited)

At May 31, 2015, the Fund's portfolio composition¹ was as follows:

Portfolio Composition	Percentage of Total Net Assets
Variable Rate Demand Instruments	80.6%
Municipal Notes	19.3%
Other Assets and Liabilities—Net2	0.1%
TOTAL	100.0%

At May 31, 2015, the Fund's effective maturity schedule³ was as follows:

Securities with an Effective Maturity of:	Percentage of Total Net Assets
1-7 Days	79.5%
8-30 Days	4.9%
31-90 Days	6.8%
91-180 Days	2.6%
181 Days or more	6.1%
Other Assets and Liabilities—Net2	0.1%
TOTAL	100.0%

1	See the Fund's Prospectus and Statement of Additional Information for a description of these investments.
2	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.
3	Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940, which regulates money market mutual funds.

Annual Shareholder Report

1

Portfolio of Investments

May 31, 2015

Principal Amount			Value
		SHORT-TERM MUNICIPALS—99.9%1,2
		Alabama—0.2%
$370,000		Montgomery, AL IDB, (Series 2001) Weekly VRDNs (Hager Hinge)/(U.S. Bank, N.A. LOC), 0.210%, 6/4/2015	$370,000
		Arizona—8.1%
555,000		Casa Grande, AZ IDA, (Series 2002A) Weekly VRDNs (Price Cos., Inc.)/(Bank of America N.A. LOC), 0.200%, 6/4/2015	555,000
7,221,000		Flagstaff, AZ IDA, (Series 1999) Weekly VRDNs (Joy Cone Co.)/(Citizens Bank of Pennsylvania LOC), 0.160%, 6/4/2015	7,221,000
5,610,000		Maricopa County, AZ, IDA, (Series 1999) Weekly VRDNs (Redman Homes, Inc.)/(Wells Fargo & Co. LOC), 0.140%, 6/4/2015	5,610,000
6,750,000		Pinal County, AZ IDA, (Series 2002) Weekly VRDNs (Milky Way Dairy LLC)/(Rabobank Nederland NV, Utrecht LOC), 0.160%, 6/4/2015	6,750,000
		TOTAL	20,136,000
		California—2.7%
6,840,000	3,4	San Francisco, CA City & County Airport Commission, SPEARs (Series DBE-1382) Weekly VRDNs (GTD by Deutsche Bank AG)/(Deutsche Bank AG LIQ), 0.200%, 6/4/2015	6,840,000
		Florida—7.3%
85,000	3,4	Clipper Tax-Exempt Certificates Trust (Florida AMT)/(Series 2009-75) Weekly VRDNs (GNMA COL)/(State Street Bank and Trust Co. LIQ), 0.220%, 6/4/2015	85,000
5,545,000		Collier County, FL IDA, (Series 2005) Weekly VRDNs (Ave Maria Utility Company)/(SunTrust Bank LOC), 0.320%, 6/3/2015	5,545,000
6,980,000	3,4	Hillsborough County, FL Aviation Authority, SPEARs (Series DBE-645) Weekly VRDNs (GTD by Deutsche Bank AG)/(Deutsche Bank AG LIQ), 0.200%, 6/4/2015	6,980,000
5,745,000		UCF Health Facilities Corp., FL, Capital Improvement Revenue Bonds (Series 2007) Weekly VRDNs (UCF Health Sciences Campus at Lake Nona)/(Fifth Third Bank, Cincinnati LOC), 0.190%, 6/5/2015	5,745,000
		TOTAL	18,355,000
		Georgia—14.9%
3,350,000		Atlanta, GA, Urban Residential Finance Authority, (Series 1995) Weekly VRDNs (West End Housing Development)/(FNMA LOC), 0.230%, 6/4/2015	3,350,000
1,500,000		Atlanta, GA, Urban Residential Finance Authority, (Series 2006) Weekly VRDNs (Columbia at Sylvan Hills Apartments)/(FNMA LOC), 0.160%, 6/4/2015	1,500,000
10,000,000		Burke County, GA Development Authority, (Third Series 2012) Daily VRDNs (Georgia Power Co.), 0.130%, 6/1/2015	10,000,000

Annual Shareholder Report

2

Principal Amount			Value
		SHORT-TERM MUNICIPALS—continued1,2
		Georgia—continued
$2,000,000	3,4	Clarke County, GA Hospital Authority, Solar Eclipse (Series 2007-0031) Weekly VRDNs (Athens Regional Medical Center)/(U.S. Bank, N.A. LIQ)/(U.S. Bank, N.A. LOC), 0.130%, 6/4/2015	$2,000,000
5,500,000		DeKalb County, GA MFH Authority, (Series 2004) Weekly VRDNs (Highlands at East Atlanta Apartments)/(Mizuho Bank Ltd. LOC), 0.160%, 6/4/2015	5,500,000
2,250,000		Fulton County, GA Development Authority, (Series 2008) Weekly VRDNs (Children's Healthcare of Atlanta, Inc.)/(Landesbank Hessen-Thuringen LIQ), 0.130%, 6/3/2015	2,250,000
3,000,000		Kennesaw, GA Development Authority, (Series 2004) Weekly VRDNs (Lakeside Vista Apartments)/(FNMA LOC), 0.160%, 6/4/2015	3,000,000
2,000,000		Putnam County, GA Development Authority, (Second Series 1997) Daily VRDNs (Georgia Power Co.), 0.110%, 6/1/2015	2,000,000
7,750,000		Savannah, GA EDA, (Series 1995A) Weekly VRDNs (Home Depot, Inc.), 0.130%, 6/3/2015	7,750,000
		TOTAL	37,350,000
		Illinois—7.1%
1,250,000		Illinois Development Finance Authority IDB, (Series 1997) Weekly VRDNs (Tempco Electric Heater Corp.)/(JPMorgan Chase Bank, N.A. LOC), 0.340%, 6/4/2015	1,250,000
1,000,000		Illinois Development Finance Authority IDB, (Series 2001) Weekly VRDNs (Apogee Enterprises, Inc.)/(Comerica Bank LOC), 0.200%, 6/4/2015	1,000,000
3,885,000		Illinois Finance Authority—Solid Waste, (Series 2013) Weekly VRDNs (Kuusakoski US LLC)/(Fifth Third Bank, Cincinnati LOC), 0.250%, 6/3/2015	3,885,000
2,450,000		Illinois Finance Authority, (Series 2008) Weekly VRDNs (Jasper Meats, Inc.)/(BMO Harris Bank, N.A. LOC), 0.220%, 6/4/2015	2,450,000
3,300,000		Lockport, IL IDA, (Series 1990) Weekly VRDNs (Panduit Corp.)/(Fifth Third Bank, Cincinnati LOC), 0.220%, 6/3/2015	3,300,000
5,800,000		Orland Park, IL IDA, (Series 1996) Weekly VRDNs (Panduit Corp.)/(Fifth Third Bank, Cincinnati LOC), 0.220%, 6/3/2015	5,800,000
		TOTAL	17,685,000
		Indiana—3.2%
5,500,000		Indianapolis, IN MFH, (Series 2007A: Forest Ridge Apartments) Weekly VRDNs (Pedcor Investments-2006-LXXXVIII LP)/(Citizens Bank, N.A., Providence LOC), 0.250%, 6/4/2015	5,500,000
2,400,000		Whiting, IN Environmental Facilities, Revenue Bonds (Series 2009), 5.00% Bonds (BP PLC), 1/1/2016	2,464,724
		TOTAL	7,964,724
		Kentucky—0.8%
2,070,000		Kentucky Housing Corp., (Series 2007) Weekly VRDNs (Arbors of Madisonville Apartments LP)/(U.S. Bank, N.A. LOC), 0.300%, 6/4/2015	2,070,000

Annual Shareholder Report

3

Principal Amount			Value
		SHORT-TERM MUNICIPALS—continued1,2
		Louisiana—2.3%
$2,200,000		Port of New Orleans, LA, (Series 2000) Weekly VRDNs (New Orleans Steamboat Co.)/(FHLB of Dallas LOC), 0.230%, 6/4/2015	$2,200,000
3,000,000		St. James Parish, LA, (Series 2009) Weekly VRDNs (Louisiana Sugar Refining, LLC)/(Natixis LOC), 0.250%, 6/4/2015	3,000,000
500,000		St. James Parish, LA, (Series 2010B-1) Weekly VRDNs (Nucor Steel Louisiana LLC)/(GTD by Nucor Corp.), 0.280%, 6/3/2015	500,000
		TOTAL	5,700,000
		Michigan—6.1%
3,950,000		Michigan State Finance Authority Revenue, (Series C) Weekly VRDNs (Fifth Third Bank, Cincinnati LOC), 0.200%, 6/3/2015	3,950,000
1,450,000		Michigan State Finance Authority Revenue, Healthcare Equipment Program (Series C) Weekly VRDNs (Fifth Third Bank, Cincinnati LOC), 0.200%, 6/3/2015	1,450,000
9,895,000		Michigan State Housing Development Authority, (Series 2007E) Weekly VRDNs (Bank of Tokyo-Mitsubishi UFJ Ltd. LIQ), 0.160%, 6/3/2015	9,895,000
		TOTAL	15,295,000
		Missouri—0.9%
2,370,000		St. Louis County, MO IDA, (Series 2008A) Daily VRDNs (International Lutheran Laymen's League)/(Fifth Third Bank, Cincinnati LOC), 0.130%, 6/1/2015	2,370,000
		Multi-State—12.8%
130,000	3,4	Clipper Tax-Exempt Certificates Trust (Multi-State AMT)/(Series 2009-68) Weekly VRDNs (GNMA COL)/(State Street Bank and Trust Co. LIQ), 0.250%, 6/4/2015	130,000
259,000	3,4	Clipper Tax-Exempt Certificates Trust (Multi-State AMT)/(Series 2009-78) Weekly VRDNs (State Street Bank and Trust Co. LIQ), 0.250%, 6/4/2015	259,000
6,700,000	3,4	Nuveen Dividend Advantage Municipal Fund 2, Weekly VRDPs (Series 2)/(Toronto Dominion Bank LIQ), 0.190%, 6/4/2015	6,700,000
5,000,000	3,4	Nuveen Investment Quality Municipal Fund, Inc., Weekly VRDPs (2,118 Series 1)/(Barclays Bank PLC LIQ), 0.190%, 6/4/2015	5,000,000
5,000,000	3,4	Nuveen Municipal Market Opportunity Fund, Inc., Weekly VRDPs (Series 1)/(Toronto Dominion Bank LIQ), 0.190%, 6/4/2015	5,000,000
5,000,000	3,4	Nuveen Premier Municipal Income Fund, Inc., Weekly VRDPs (1.277 Series 1)/(Barclays Bank PLC LIQ), 0.190%, 6/4/2015	5,000,000
10,000,000	3,4	Nuveen Premium Income Municipal Fund 4, Inc., Weekly VRDPs (Series 1)/(JPMorgan Chase Bank NA LIQ), 0.180%, 6/4/2015	10,000,000
		TOTAL	32,089,000
		Nevada—2.0%
5,000,000		Clark County, NV Airport System, (Series C-1), 2.50% Bonds, 7/1/2015	5,009,568
		New Jersey—3.6%
6,000,000		Belmar, NJ, 1.25% BANs, 2/12/2016	6,032,656

Annual Shareholder Report

4

Principal Amount			Value
		SHORT-TERM MUNICIPALS—continued1,2
		New Jersey—continued
$3,000,000		Hazlet Township, NJ, 1.00% BANs, 6/22/2015	$3,000,822
		TOTAL	9,033,478
		New York—8.4%
2,140,000		Ausable Valley, NY CSD, 0.75% BANs, 6/25/2015	2,140,433
3,000,000		East Moriches, NY UFSD, 1.00% TANs, 6/19/2015	3,000,973
1,300,000		New York City, NY IDA, IDRBs (Series 2003) Weekly VRDNs (Novelty Crystal Corp.)/(TD Bank, N.A. LOC), 0.240%, 6/4/2015	1,300,000
14,500,000	3,4	Nuveen NY AMT-Free Municipal Income Fund, Weekly VRDPs (Series 1)/(Citibank N.A. LIQ), 0.160%, 6/4/2015	14,500,000
		TOTAL	20,941,406
		North Carolina—0.6%
1,600,000		Hertford County, NC Industrial Facilities & PCFA, (Series 2000B) Weekly VRDNs (Nucor Corp.), 0.250%, 6/3/2015	1,600,000
		Ohio—8.8%
4,000,000		Avon Lake, OH, 1.00% BANs, 7/14/2015	4,003,572
3,900,000		Avon, OH Water System, 1.00% BANs, 2/3/2016	3,917,069
1,400,000		Canton, OH, 1.00% BANs, 6/19/2015	1,400,412
1,000,000		Hamilton County, OH Hospital Facilities Authority, (Series 2002A) Weekly VRDNs (The Elizabeth Gamble Deaconess Home Association)/(Northern Trust Co., Chicago, IL LOC), 0.130%, 6/4/2015	1,000,000
2,800,000		Montgomery, OH, 1.00% BANs, 6/24/2015	2,801,320
1,280,000		Newark, OH, 1.00% BANs, 7/23/2015	1,281,220
1,100,000		Ohio State Air Quality Development Authority, (Series 2009C) Weekly VRDNs (Ohio Valley Electric Corp.)/(Bank of Tokyo-Mitsubishi UFJ Ltd. LOC), 0.100%, 6/4/2015	1,100,000
3,935,000		Ontario, OH, 1.00% BANs, 10/22/2015	3,945,283
2,500,000		West Chester Township, OH, 1.625% BANs, 11/4/2015	2,514,111
		TOTAL	21,962,987
		Pennsylvania—1.2%
3,000,000		Pittsburgh & Allegheny County, PA Sports & Exhibition Authority, (Series A of 2007) Weekly VRDNs (Assured Guaranty Municipal Corp. INS)/(PNC Bank, N.A. LIQ), 0.200%, 6/4/2015	3,000,000
		South Carolina—1.3%
3,030,000		South Carolina Jobs-EDA, (Series 2007) Weekly VRDNs (ACI Industries LLC)/(Bank of America N.A. LOC), 0.280%, 6/4/2015	3,030,000
110,000		South Carolina Jobs-EDA, (Series 2007A) Weekly VRDNs (Woodhead LLC)/(FHLB of Atlanta LOC), 0.200%, 6/4/2015	110,000
		TOTAL	3,140,000
		Virginia—6.8%
2,750,000		Arlington County, VA IDA, (Series 2005) Weekly VRDNs (Gates of Ballston Apartments)/(PNC Bank, N.A. LOC), 0.100%, 6/3/2015	2,750,000

Annual Shareholder Report

5

Principal Amount			Value
		SHORT-TERM MUNICIPALS—continued1,2
		Virginia—continued
$2,925,000		Fairfax County, VA IDA, (Inova Health System) MVRENs, (Series 2012 C), 0.180%, 6/4/2015	$2,925,000
4,745,000		Fairfax County, VA IDA, (Series A-2) Weekly VRDNs (Inova Health System), 0.100%, 6/4/2015	4,745,000
6,700,000	3,4	Virginia State Housing Development Authority, Stage Trust (Series 2008-47C), 0.24% TOBs (Wells Fargo & Co. LIQ), Optional Tender 7/8/2015	6,700,000
		TOTAL	17,120,000
		Wisconsin—0.8%
2,000,000		Combined Locks, WI IDRB, (Series 1997) Weekly VRDNs (Appleton Papers)/(Fifth Third Bank, Cincinnati LOC), 0.270%, 6/4/2015	2,000,000
		TOTAL MUNICIPAL INVESTMENTS—99.9% (AT AMORTIZED COST)5	250,032,163
		OTHER ASSETS AND LIABILITIES - NET—0.1%6	128,945
		TOTAL NET ASSETS—100%	$250,161,108

Securities that are subject to the federal alternative minimum tax (AMT) represent 65.1% of the portfolio as calculated based upon total market value (percentage is unaudited).

1	The Fund may only invest in securities rated in one of the two highest short-term rating categories by nationally recognized statistical rating organizations (NRSROs) or unrated securities of comparable quality. An NRSRO's two highest rating categories are determined without regard for sub-categories and gradations. For example, securities rated SP-1+, SP-1 or SP-2 by Standard & Poor's, MIG-1 or MIG-2 by Moody's Investors Service, or F-1+, F-1 or F-2 by Fitch Ratings, are all considered rated in one of the two highest short-term rating categories.
	Securities rated in the highest short-term rating category (and unrated securities of comparable quality) are identified as First Tier securities. Securities rated in the second highest short-term rating category (and unrated securities of comparable quality) are identified as Second Tier securities. The Fund follows applicable regulations in determining whether a security is rated and whether a security rated by multiple NRSROs in different rating categories should be identified as a First or Second Tier security.
	At May 31, 2015, the portfolio securities were rated as follows:
	Tier Rating Percentages Based on Total Market Value (unaudited)

First Tier	Second Tier
99.2%	0.8%

2	Current rate and next reset date shown for Variable Rate Demand Instruments.
3	Denotes a restricted security that either: (a) cannot be offered for public sale without first being registered, or being able to take advantage of an exemption from registration, under the Securities Act of 1933; or (b) is subject to a contractual restriction on public sales. At May 31, 2015, these restricted securities amounted to $69,194,000, which represented 27.7% of total net assets.
4	Denotes a restricted security that may be resold without restriction to “qualified institutional buyers” as defined in Rule 144A under the Securities Act of 1933 and that the Fund has determined to be liquid under criteria established by the Fund's Board of Directors (the “Directors”). At May 31, 2015, these liquid restricted securities amounted to $69,194,000, which represented 27.7% of total net assets.

Annual Shareholder Report

6

5	Also represents cost for federal tax purposes.
6	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.

Note: The categories of investments are shown as a percentage of total net assets at May 31, 2015.

Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below:

Level 1—quoted prices in active markets for identical securities.

Level 2—other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.). Also includes securities valued at amortized cost.

Level 3—significant unobservable inputs (including the Fund's own assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities.

As of May 31, 2015, all investments of the Fund are valued at amortized cost, which is considered a Level 2 input, in valuing the Fund's assets.

The following acronyms are used throughout this portfolio:

AMT	—Alternative Minimum Tax
BANs	—Bond Anticipation Notes
COL	—Collateralized
CSD	—Central School District
EDA	—Economic Development Authority
FHLB	—Federal Home Loan Bank
FNMA	—Federal National Mortgage Association
GNMA	—Government National Mortgage Association
GTD	—Guaranteed
IDA	—Industrial Development Authority
IDB	—Industrial Development Bond
IDRBs	—Industrial Development Revenue Bonds
INS	—Insured
LIQ	—Liquidity Agreement
LOC	—Letter of Credit
MFH	—Multi-Family Housing
MVRENs	—Municipal Variable Rate Exchangeable Notes
PCFA	—Pollution Control Finance Authority
SPEARs	—Short Puttable Exempt Adjustable Receipts
TANs	—Tax Anticipation Notes
TOBs	—Tender Option Bonds
VRDNs	—Variable Rate Demand Notes
VRDPs	—Variable Rate Demand Preferreds

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

7

Financial Highlights

(For a Share Outstanding Throughout Each Period)

Year Ended May 31	2015	2014	2013	2012	2011
Net Asset Value, Beginning of Period	$1.00	$1.00	$1.00	$1.00	$1.00
Income From Investment Operations:
Net investment income	—	—	—	—	—
Net realized gain on investments	—	0.0001	0.0001	0.0001	0.0001
TOTAL FROM INVESTMENT OPERATIONS	—	0.0001	0.0001	0.0001	0.0001
Less Distributions:
Distributions from net realized gain on investments	(0.000)1	(0.000)1	(0.000)1	(0.000)1	(0.000)1
Net Asset Value, End of Period	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return2	0.00%3	0.02%	0.00%3	0.00%3	0.00%3
Ratios to Average Net Assets:
Net expenses	0.18%	0.23%	0.31%	0.42%	0.49%
Net investment income	0.00%	0.00%	0.00%	0.00%	0.00%
Expense waiver/reimbursement4	0.94%	0.89%	0.72%	0.68%	0.59%
Supplemental Data:
Net assets, end of period (000 omitted)	$250,161	$317,849	$360,830	$461,541	$539,081

1	Represents less than $0.001.
2	Based on net asset value.
3	Represents less than 0.01%.
4	This expense decrease is reflected in both the net expense and the net investment income ratios shown above.

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

8

Statement of Assets and Liabilities

May 31, 2015

Assets:
Total investment in securities, at amortized cost and fair value		$250,032,163
Income receivable		381,140
Receivable for shares sold		15,073
TOTAL ASSETS		250,428,376
Liabilities:
Payable for shares redeemed	$14,745
Bank overdraft	160,664
Payable to adviser (Note 5)	21,911
Payable for transfer agent fee	18,018
Payable for Directors'/Trustees' fees (Note 5)	542
Payable for portfolio accounting fees	10,886
Payable for share registration costs	31,274
Accrued expenses (Note 5)	9,228
TOTAL LIABILITIES		267,268
Net assets for 250,168,101 shares outstanding		$250,161,108
Net Assets Consist of:
Paid-in capital		$250,161,108
TOTAL NET ASSETS		$250,161,108
Net Asset Value, Offering Price and Redemption Proceeds Per Share:
$250,161,108 ÷ 250,168,101 shares outstanding, $0.001 par value, 12,500,000,000 shares authorized		$1.00

See Notes which are an integral part of the Financial Statements

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Statement of Operations

Year Ended May 31, 2015

Investment Income:
Interest			$523,601
Expenses:
Investment adviser fee (Note 5)		$1,417,521
Administrative fee (Note 5)		221,822
Custodian fees		11,501
Transfer agent fee		309,594
Directors'/Trustees' fees (Note 5)		3,436
Auditing fees		19,600
Legal fees		12,858
Portfolio accounting fees		74,360
Distribution services fee (Note 5)		283,504
Other service fees (Note 2)		708,998
Share registration costs		80,244
Printing and postage		30,408
Taxes		21,429
Miscellaneous (Note 5)		6,337
TOTAL EXPENSES		3,201,612
Waivers and Reimbursement:
Waiver of investment adviser fee (Note 5)	$(1,409,753)
Waivers/reimbursement of other operating expenses (Notes 2 and 5)	(1,268,258)
TOTAL WAIVERS AND REIMBURSEMENT		(2,678,011)
Net expenses			523,601
Net investment income			—

See Notes which are an integral part of the Financial Statements

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Statement of Changes in Net Assets

Year Ended May 31	2015	2014
Increase (Decrease) in Net Assets
Operations:
Net investment income	$—	$—
Net realized gain on investments	—	47,381
CHANGE IN NET ASSETS RESULTING FROM OPERATIONS	—	47,381
Distributions to Shareholders:
Distributions from net realized gain on investments	(4,693)	(49,428)
Share Transactions:
Proceeds from sale of shares	289,415,069	425,851,930
Net asset value of shares issued to shareholders in payment of distributions declared	4,677	49,203
Cost of shares redeemed	(357,102,871)	(468,880,352)
CHANGE IN NET ASSETS RESULTING FROM SHARE TRANSACTIONS	(67,683,125)	(42,979,219)
Change in net assets	(67,687,818)	(42,981,266)
Net Assets:
Beginning of period	317,848,926	360,830,192
End of period	$250,161,108	$317,848,926

See Notes which are an integral part of the Financial Statements

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Notes to Financial Statements

May 31, 2015

1. ORGANIZATION

Cash Trust Series, Inc. (the “Corporation”) is registered under the Investment Company Act of 1940, as amended (the “Act”), as an open-end management investment company. The Corporation consists of four portfolios. The financial statements included herein are only those of Federated Municipal Cash Series (the “Fund”), a diversified portfolio. The financial statements of the other portfolios are presented separately. The assets of each portfolio are segregated and a shareholder's interest is limited to the portfolio in which shares are held. Each portfolio pays its own expenses. The investment objective of the Fund is to provide current income which is exempt from federal regular income tax consistent with stability of principal. Interest income from the Fund's investments may be subject to the federal AMT for individuals and corporations and state and local taxes.

2. SIGNIFICANT ACCOUNTING POLICIES

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. These policies are in conformity with U.S. generally accepted accounting principles (GAAP).

Investment Valuation

Securities are valued at amortized cost. Under the amortized cost valuation method, an investment is valued initially at its cost as determined in accordance with GAAP. The Fund then adjusts the amount of interest income accrued each day over the term of the investment to account for any difference between the initial cost of the investment and the amount payable at its maturity. If amortized cost is determined not to approximate fair value, the value of the portfolio securities will be determined in accordance with the procedures described below.

The Directors have ultimate responsibility for determining the fair value of investments. The Directors have appointed a valuation committee (“Valuation Committee”) comprised of officers of the Fund, Federated Investment Management Company (“Adviser”) and certain of the Adviser's affiliated companies to assist in determining fair value of securities and in overseeing the comparison of amortized cost to market-based value. The Directors have also authorized the use of pricing services recommended by the Valuation Committee to provide fair value evaluations of the current value of certain investments for purposes of monitoring the relationship of market-based value and amortized cost. The Valuation Committee employs various methods for reviewing third-party pricing-service evaluations including periodic reviews of third-party pricing services' policies, procedures and valuation methods (including key inputs and assumptions), and review of price challenges by the Adviser based on recent market activity. In the event that market quotations and price evaluations are not available for an investment, the Valuation Committee determines the fair value of the investment in accordance with procedures adopted by the Directors. The Directors periodically review and approve the fair valuations made by the Valuation Committee and any changes made to the procedures.

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Investment Income, Gains and Losses, Expenses and Distributions

Investment transactions are accounted for on a trade-date basis. Realized gains and losses from investment transactions are recorded on an identified-cost basis. Interest income and expenses are accrued daily. Distributions to shareholders are recorded on the ex-dividend date. Distributions of net investment income, if any, are declared daily and paid monthly.

For the year ended May 31, 2015, unaffiliated third parties waived $275,756 of transfer agent fees.

Other Service Fees

The Fund may pay other service fees up to 0.25% of the average daily net assets of the Fund's Shares to unaffiliated financial intermediaries or to Federated Shareholder Services Company (FSSC) for providing services to shareholders and maintaining shareholder accounts. Subject to the terms described in the Expense Limitation note, FSSC may voluntarily reimburse the Fund for other service fees. For the year ended May 31, 2015, unaffiliated third-party financial intermediaries waived their entire other service fees of $708,998. This waiver can be modified or terminated at any time.

Premium and Discount Amortization

All premiums and discounts are amortized/accreted using the effective-interest-rate method.

Federal Taxes

It is the Fund's policy to comply with the Subchapter M provision of the Internal Revenue Code and to distribute to shareholders each year substantially all of its income. Accordingly, no provision for federal income tax is necessary. As of and during the year ended May 31, 2015, the Fund did not have a liability for any uncertain tax positions. The Fund recognizes interest and penalties, if any, related to tax liabilities as income tax expense in the Statement of Operations. As of May 31, 2015, tax years 2012 through 2015 remain subject to examination by the Fund's major tax jurisdictions, which include the United States of America, the state of Maryland and the Commonwealth of Pennsylvania.

Other Taxes

As an open-end management investment company incorporated in the state of Maryland but domiciled in the Commonwealth of Pennsylvania, the Fund is subject to the Pennsylvania Franchise Tax. This franchise tax is assessed annually on the value of the Fund, as represented by average net assets for the tax year.

When-Issued and Delayed-Delivery Transactions

The Fund may engage in when-issued or delayed-delivery transactions. The Fund records when-issued securities on the trade date and maintains security positions such that sufficient liquid assets will be available to make payment for the securities purchased. Securities purchased on a when-issued or delayed-delivery basis are marked to market daily and begin earning interest on the settlement date. Losses may occur on these transactions due to changes in market conditions or the failure of counterparties to perform under the contract.

Restricted Securities

The Fund may purchase securities which are considered restricted. Restricted securities are securities that either: (a) cannot be offered for public sale without first being registered, or being able to take advantage of an exemption from registration, under the Securities Act of 1933; or (b) are subject to contractual restrictions on public sales. In some cases, when a security cannot be offered for public sale without first being registered, the issuer of the

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restricted security has agreed to register such securities for resale, at the issuer's expense, either upon demand by the Fund or in connection with another registered offering of the securities. Many such restricted securities may be resold in the secondary market in transactions exempt from registration. Restricted securities may be determined to be liquid under criteria established by the Directors. The Fund will not incur any registration costs upon such resales. Restricted securities are valued at amortized cost in accordance with Rule 2a-7 under the Act.

Other

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, expenses and revenues reported in the financial statements. Actual results could differ from those estimated. The Fund applies Investment Company accounting and reporting guidance.

3. CAPITAL STOCK

The following table summarizes capital stock activity:

Year Ended May 31	2015	2014
Shares sold	289,415,069	425,851,930
Shares issued to shareholders in payment of distributions declared	4,677	49,203
Shares redeemed	(357,102,871)	(468,880,352)
NET CHANGE RESULTING FROM FUND SHARE TRANSACTIONS	(67,683,125)	(42,979,219)

4. FEDERAL TAX INFORMATION

The tax character of distributions as reported on the Statement of Changes in Net Assets for the years ended May 31, 2015 and 2014 was as follows:

	2015	2014
Ordinary income1	$4,586	$41,289
Long-term capital gains	$107	$8,139

1 For tax purposes, short-term capital gain distributions are considered ordinary income distributions.

5. INVESTMENT ADVISER FEE AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Adviser Fee

The advisory agreement between the Fund and the Adviser provides for an annual fee equal to 0.50% of the Fund's average daily net assets. Subject to the terms described in the Expense Limitation note, the Adviser may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2015, the Adviser voluntarily waived $1,409,753 of its fee.

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Administrative Fee

Federated Administrative Services (FAS), under the Administrative Services Agreement, provides the Fund with administrative personnel and services. For purposes of determining the appropriate rate breakpoint, “Investment Complex” is defined as all of the Federated Funds subject to a fee under the Administrative Services Agreement. The fee paid to FAS is based on the average daily net assets of the Investment Complex as specified below, plus certain out-of-pocket expenses:

Administrative Fee	Average Daily Net Assets of the Investment Complex
0.150%	on the first $5 billion
0.125%	on the next $5 billion
0.100%	on the next $10 billion
0.075%	on assets in excess of $20 billion

Subject to the terms described in the Expense Limitation note, FAS may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2015, the annualized fee paid to FAS was 0.078% of average daily net assets of the Fund.

Distribution Services Fee

The Fund has adopted a Distribution Plan (the “Plan”) pursuant to Rule 12b-1 under the Act. Under the terms of the Plan, the Fund will reimburse Federated Securities Corp. (FSC), the principal distributor, from the daily net assets of the Fund to finance activities intended to result in the sale of these shares. The Plan provides that the Fund may incur distribution expenses of up to 0.35% of average daily net assets, annually, to reimburse FSC. Subject to the terms described in the Expense Limitation note, FSC may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2015, FSC voluntarily waived its entire fee of $283,504. When FSC receives fees, it may pay some or all of them to financial intermediaries whose customers purchase shares.

Expense Limitation

Due to the possibility of changes in market conditions and other factors, there can be no assurance that the level of waivers/reimbursement/reduction of Fund expenses reflected in the financial highlights will be maintained in the future. However, the Adviser and certain of its affiliates (which may include FSC, FAS and FSSC), on their own initiative, have agreed to waive certain amounts of their respective fees and/or reimburse expenses. Total annual fund operating expenses (as shown in the financial highlights, excluding extraordinary expenses and proxy-related expenses paid by the Fund, if any) paid by the Fund's Shares (after the voluntary waivers and/or reimbursements) will not exceed 1.05% (the “Fee Limit”), up to but not including the later of (the “Termination Date”): (a) August 1, 2016; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its applicable affiliates currently do not anticipate terminating or increasing this arrangement prior to the Termination Date, this arrangement may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Directors.

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Interfund Transactions

During the year ended May 31, 2015, the Fund engaged in purchase and sale transactions with funds that have a common investment adviser (or affiliated investment advisers), common Directors/Trustees, and/or common Officers. These purchase and sale transactions complied with Rule 17a-7 under the Act and amounted to $614,910,000 and $625,495,000, respectively.

General

Certain Officers and Directors of the Fund are Officers and Directors or Trustees of certain of the above companies. To efficiently facilitate payment, Directors'/Trustees' fees and certain expenses related to conducting meetings of the Directors/Trustees and other miscellaneous expenses are paid by an affiliate of the Adviser which in due course are reimbursed by the Fund. Such expenses may be included in Accrued and Miscellaneous Expenses on the Statement of Assets and Liabilities and Statement of Operations, respectively.

6. LINE OF CREDIT

The Fund participates in a $100,000,000 unsecured, uncommitted revolving line of credit (LOC) agreement with PNC Bank. The LOC was made available for extraordinary or emergency purposes, primarily for financing redemption payments. Borrowings are charged interest at a rate offered to the Fund by PNC Bank at the time of the borrowing. As of May 31, 2015, there were no outstanding loans. During the year ended May 31, 2015, the Fund did not utilize the LOC.

7. INTERFUND LENDING

Pursuant to an Exemptive Order issued by the Securities and Exchange Commission (SEC), the Fund, along with other funds advised by subsidiaries of Federated Investors, Inc., may participate in an interfund lending program. This program provides an alternative credit facility allowing the Fund to borrow from other participating affiliated funds. As of May 31, 2015, there were no outstanding loans. During the year ended May 31, 2015, the program was not utilized.

8. REGULATORY MATTERS

On July 23, 2014, the SEC voted to amend the rules under the Act which currently govern the operations of the Fund. A significant change resulting from these amendments will be a requirement that institutional prime funds (i.e. not retail as defined in the amendments), transact fund shares based on a market-based Net Asset Value (NAV). Other types of money market funds may continue to transact fund shares at an NAV calculated using the amortized cost valuation method. Among additional disclosure and other requirements, the amendments also will permit a money market fund, or, in certain circumstances, require a money market fund (other than a government money market fund which satisfies the requirements of the amended rules) to impose liquidity fees on redemptions, and permit a money market fund to limit (or gate) redemptions for up to 10 business days in any 90-day period. The amendments have staggered compliance dates. Compliance with a majority of these amendments will be required on October 14, 2016, two years after the effective date for the rule amendments. The degree to which a money market fund will be impacted by the rule amendments will depend upon the type of fund and type of investors (retail or institutional). At this time, management is evaluating the implications of these amendments and their impact to the Fund's operations, financial statements and accompanying notes.

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9. SUBSEQUENT EVENT

On June 3, 2015, the Fund filed a supplement to its current Prospectus notifying shareholders that the Directors have approved a proposed Agreement and Plan of Reorganization (“Reorganization'') pursuant to which Federated Municipal Obligations Fund would acquire all or substantially all of the assets of the Fund in complete liquidation and termination of the Fund. Information statements will be sent to shareholders explaining the Reorganization. The Reorganization is expected to occur in the fourth quarter of 2015.

Management has evaluated subsequent events through the date the financial statements were issued and determined that no additional events occurred that require disclosure.

10. FEDERAL TAX INFORMATION (UNAUDITED)

For the year ended May 31, 2015, the Fund designated $107 of its distributions as long-term capital gains distributions.

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Report of Independent Registered Public Accounting Firm

TO THE BOARD OF directors OF Cash trust Series, INc. AND SHAREHOLDERS Of Federated Municipal Cash series:

We have audited the accompanying statement of assets and liabilities of Federated Municipal Cash Series (the “Fund”) (one of the portfolios constituting Cash Trust Series, Inc.), including the portfolio of investments, as of May 31, 2015, and the related statement of operations for the year then ended, the statement of changes in net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended. These financial statements and financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

We conducted our audits in accordance with standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. We were not engaged to perform an audit of the Fund's internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements and financial highlights, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of May 31, 2015, by correspondence with the custodian and others. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Federated Municipal Cash Series, a portfolio of Cash Trust Series, Inc., at May 31, 2015, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended, in conformity with U.S. generally accepted accounting principles.

Boston, Massachusetts
July 23, 2015

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Shareholder Expense Example (unaudited)

As a shareholder of the Fund, you incur ongoing costs, including management fees and to the extent applicable, distribution (12b-1) fees and/or other service fees and other Fund expenses. This Example is intended to help you to understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. It is based on an investment of $1,000 invested at the beginning of the period and held for the entire period from December 1, 2014 to May 31, 2015.

ACTUAL EXPENSES

The first section of the table below provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you incurred over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses attributable to your investment during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second section of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. Thus, you should not use the hypothetical account values and expenses to estimate the actual ending account balance or your expenses for the period. Rather, these figures are required to be provided to enable you to compare the ongoing costs of investing in the Fund with other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

	Beginning Account Value 12/1/2014	Ending Account Value 5/31/2015	Expenses Paid During Period1,2
Actual	$1,000	$1,000.10	$0.90
Hypothetical (assuming a 5% return before expenses)	$1,000	$1,024.03	$0.91

1

Expenses are equal to the Fund's annualized net expense ratio of 0.18%, multiplied by the average account value over the period, multiplied by 182/365 (to reflect the one-half-year period).

2

Actual and Hypothetical expenses paid during the period utilizing the Fund's current Fee Limit of 1.05% (as reflected in the Notes to Financial Statements, Note 5 under Expense Limitation), multiplied by the average account value over the period, multiplied by 182/365 (to reflect expenses paid as if they had been in effect throughout the most recent one-half-year period) would be $5.24 and $5.29, respectively.

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Board of Directors and Corporation Officers

The Board of Directors is responsible for managing the Corporation's business affairs and for exercising all the Corporation's powers except those reserved for the shareholders. The following tables give information about each Director and the senior officers of the Fund. Where required, the tables separately list Directors who are “interested persons” of the Fund (i.e., “Interested” Directors) and those who are not (i.e., “Independent” Directors). Unless otherwise noted, the address of each person listed is Federated Investors Tower, 1001 Liberty Avenue, Pittsburgh, PA 15222. The address of all Independent Directors listed is 4000 Ericsson Drive, Warrendale, PA 15086-7561; Attention: Mutual Fund Board. As of December 31, 2014, the Corporation comprised four portfolio(s), and the Federated Fund Family consisted of 40 investment companies (comprising 131 portfolios). Unless otherwise noted, each Officer is elected annually. Unless otherwise noted, each Director oversees all portfolios in the Federated Fund Family and serves for an indefinite term. The Fund's Statement of Additional Information includes additional information about Corporation Directors and is available, without charge and upon request, by calling 1-800-341-7400.

Interested DIRECTORS Background

Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years, Other Directorships Held and Previous Position(s)
John F. Donahue* Birth Date: July 28, 1924 Director Indefinite Term Began serving: May 1989	Principal Occupations: Director or Trustee of the Federated Fund Family; Chairman and Director, Federated Investors, Inc.; Chairman of the Federated Fund Family's Executive Committee. Previous Positions: Chairman of the Federated Fund Family; Trustee, Federated Investment Management Company; Chairman and Director, Federated Investment Counseling.

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Name Birth Date Positions Held with Corporation Date Service Began

Principal Occupation(s) for Past Five Years, Other Directorships Held and Previous Position(s)

J. Christopher Donahue* Birth Date: April 11, 1949 President and Director Indefinite Term Began serving: May 1989

Principal Occupations: Principal Executive Officer and President of certain of the Funds in the Federated Fund Family; Director or Trustee of the Funds in the Federated Fund Family; President, Chief Executive Officer and Director, Federated Investors, Inc.; Chairman and Trustee, Federated Investment Management Company; Trustee, Federated Investment Counseling; Chairman and Director, Federated Global Investment Management Corp.; Chairman, Federated Equity Management Company of Pennsylvania and Passport Research, Ltd. (investment advisory subsidiary of Federated); Trustee, Federated Shareholder Services Company; Director, Federated Services Company. Previous Positions: President, Federated Investment Counseling; President and Chief Executive Officer, Federated Investment Management Company, Federated Global Investment Management Corp. and Passport Research, Ltd.

* Family relationships and reasons for “interested” status: John F. Donahue is the father of J. Christopher Donahue; both are “interested” due to their beneficial ownership of shares of Federated Investors, Inc. and the positions they hold with Federated and its subsidiaries.

INDEPENDENT DIRECTORS Background

Name Birth Date Positions Held with Corporation Date Service Began

Principal Occupation(s) for Past Five Years, Other Directorships Held, Previous Position(s) and Qualifications

John T. Collins Birth Date: January 24, 1947 Director Indefinite Term Began serving: October 2013

Principal Occupations: Director or Trustee of the Federated Fund Family; Chairman and CEO, The Collins Group, Inc. (a private equity firm). Other Directorships Held: Director, Chair of the Compensation Committee, Audit Committee member, KLX Corp. Qualifications: Mr. Collins has served in several business and financial management roles and directorship positions throughout his career. Mr. Collins serves as Chairman Emeriti, Bentley University. Mr. Collins previously served as Director, FleetBoston Financial Corp.; Director and Audit Committee Member, Bank of America Corp. and Director, Beth Israel Deaconess Medical Center (Harvard University Affiliate Hospital).

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Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years, Other Directorships Held, Previous Position(s) and Qualifications
Maureen Lally-Green Birth Date: July 5, 1949 Director Indefinite Term Began serving: August 2009	Principal Occupations: Director or Trustee of the Federated Fund Family; Adjunct Professor of Law, Duquesne University School of Law. Other Directorships Held: Director, CONSOL Energy Inc. Qualifications: Judge Lally-Green has served in various legal and business roles and directorship positions throughout her career. Judge Lally-Green previously served as: Associate General Secretary, Diocese of Pittsburgh; Professor of Law, Duquesne University School of Law and was a member of the Superior Court of Pennsylvania. Judge Lally-Green also holds the positions of: Member, Pennsylvania State Board of Education; Director, Saint Vincent College; Director and Chair, UPMC Mercy Hospital; Regent, St. Vincent Seminary; Director, Epilepsy Foundation of Western and Central Pennsylvania; Director, Our Campaign for the Church Alive!, Inc.; Director, Pennsylvania Bar Institute; and Director, Catholic High Schools of the Diocese of Pittsburgh, Inc. Judge Lally-Green has held the positions of: Director, Auberle; Director, Ireland Institute of Pittsburgh; Director, Saint Thomas More Society; and Director Cardinal Wuerl Catholic High School.
Peter E. Madden Birth Date: March 16, 1942 Director Indefinite Term Began serving: August 1991	Principal Occupation: Director or Trustee, and Chair of the Board of Directors or Trustees, of the Federated Fund Family; Retired. Other Directorships Held: None. Qualifications: Mr. Madden has served in several business management, mutual fund services and directorship positions throughout his career. Mr. Madden previously served as President, Chief Operating Officer and Director, State Street Bank and Trust Company (custodian bank) and State Street Corporation (financial services). He was Director, VISA USA and VISA International and Chairman and Director, Massachusetts Bankers Association. Mr. Madden served as Director, Depository Trust Corporation and Director, The Boston Stock Exchange. Mr. Madden also served as a Representative to the Commonwealth of Massachusetts General Court.
Charles F. Mansfield, Jr. Birth Date: April 10, 1945 Director Indefinite Term Began serving: January 1999	Principal Occupations: Director or Trustee of the Federated Fund Family; Management Consultant. Other Directorships Held: None. Qualifications: Mr. Mansfield has served in several banking, business management and educational roles and directorship positions throughout his career. Mr. Mansfield previously served as Chief Executive Officer, PBTC International Bank; Partner, Arthur Young & Company (now Ernst & Young LLP); Chief Financial Officer of Retail Banking Sector, Chase Manhattan Bank; Senior Vice President, HSBC Bank USA (formerly, Marine Midland Bank); Vice President, Citibank; Assistant Professor of Banking and Finance, Frank G. Zarb School of Business, Hofstra University; Executive Vice President DVC Group, Inc. (marketing, communications and technology).

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Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years, Other Directorships Held, Previous Position(s) and Qualifications
Thomas M. O'Neill Birth Date: June 14, 1951 Director Indefinite Term Began serving: October 2006	Principal Occupations: Director or Trustee, Vice Chair of the Audit Committee of the Federated Fund Family; Sole Proprietor, Navigator Management Company (investment and strategic consulting). Other Directorships Held: None. Qualifications: Mr. O'Neill has served in several business, mutual fund and financial management roles and directorship positions throughout his career. Mr. O'Neill serves as Director, Medicines for Humanity and Director, The Golisano Children's Museum of Naples, Florida. Mr. O'Neill previously served as Chief Executive Officer and President, Managing Director and Chief Investment Officer, Fleet Investment Advisors; President and Chief Executive Officer, Aeltus Investment Management, Inc.; General Partner, Hellman, Jordan Management Co., Boston, MA; Chief Investment Officer, The Putnam Companies, Boston, MA; Credit Analyst and Lending Officer, Fleet Bank; Director and Consultant, EZE Castle Software (investment order management software); and Director, Midway Pacific (lumber).
P. Jerome Richey Birth Date: February 23, 1949 Director Indefinite Term Began serving: October 2013	Principal Occupations: Director or Trustee of the Federated Fund Family; Management Consultant. Other Directorships Held: None. Qualifications: Mr. Richey has served in several business and legal management roles and directorship positions throughout his career. Mr. Richey most recently held the positions of Senior Vice Chancellor and Chief Legal Officer, University of Pittsburgh. Mr. Richey serves as Board Member, Epilepsy Foundation of Western Pennsylvania and Board member, World Affairs Council of Pittsburgh. Mr. Richey previously served as Chief Legal Officer and Executive Vice President, CONSOL Energy Inc. and Shareholder, Buchanan Ingersoll & Rooney PC (a law firm).
John S. Walsh Birth Date: November 28, 1957 Director Indefinite Term Began serving: January 1999	Principal Occupations: Director or Trustee, Chair of the Audit Committee of the Federated Fund Family; President and Director, Heat Wagon, Inc. (manufacturer of construction temporary heaters); President and Director, Manufacturers Products, Inc. (distributor of portable construction heaters); President, Portable Heater Parts, a division of Manufacturers Products, Inc. Other Directorships Held: None. Qualifications: Mr. Walsh has served in several business management roles and directorship positions throughout his career. Mr. Walsh previously served as Vice President, Walsh & Kelly, Inc. (paving contractors).

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OFFICERS

Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years and Previous Position(s)
John W. McGonigle Birth Date: October 26, 1938 EXECUTIVE VICE PRESIDENT AND SECRETARY Officer since: May 1989	Principal Occupations: Executive Vice President and Secretary of the Federated Fund Family; Vice Chairman, Executive Vice President, Secretary and Director, Federated Investors, Inc. Previous Positions: Trustee, Federated Investment Management Company and Federated Investment Counseling; Director, Federated Global Investment Management Corp., Federated Services Company and Federated Securities Corp.
Lori A. Hensler Birth Date: January 6, 1967 TREASURER Officer since: April 2013	Principal Occupations: Principal Financial Officer and Treasurer of the Federated Fund Family; Senior Vice President, Federated Administrative Services; Financial and Operations Principal for Federated Securities Corp. and Edgewood Services, Inc.; and Assistant Treasurer, Federated Investors Trust Company. Ms. Hensler has received the Certified Public Accountant designation. Previous Positions: Controller of Federated Investors, Inc.; Senior Vice President and Assistant Treasurer, Federated Investors Management Company; Treasurer, Federated Investors Trust Company; Assistant Treasurer, Federated Administrative Services, Federated Administrative Services, Inc., Federated Securities Corp., Edgewood Services, Inc., Federated Advisory Services Company, Federated Equity Management Company of Pennsylvania, Federated Global Investment Management Corp., Federated Investment Counseling, Federated Investment Management Company, Passport Research, Ltd., and Federated MDTA, LLC; Financial and Operations Principal for Federated Securities Corp., Edgewood Services, Inc. and Southpointe Distribution Services, Inc.
Peter J. Germain Birth Date: September 3, 1959 CHIEF LEGAL OFFICER Officer since: January 2005	Principal Occupations: Mr. Germain is Chief Legal Officer of the Federated Fund Family. He is General Counsel and Vice President, Federated Investors, Inc.; President, Federated Administrative Services and Federated Administrative Services, Inc.; Vice President, Federated Securities Corp.; Secretary, Federated Private Asset Management, Inc.; and Secretary, Retirement Plan Service Company of America. Mr. Germain joined Federated in 1984 and is a member of the Pennsylvania Bar Association. Previous Positions: Deputy General Counsel, Special Counsel, Managing Director of Mutual Fund Services, Federated Investors, Inc.; Senior Vice President, Federated Services Company; and Senior Corporate Counsel, Federated Investors, Inc.
Richard B. Fisher Birth Date: May 17, 1923 Vice Chairman Officer since: August 2002	Principal Occupations: Vice Chairman or Vice President of some of the Funds in the Federated Fund Family; Vice Chairman, Federated Investors, Inc.; Chairman, Federated Securities Corp. Previous Positions: President and Director or Trustee of some of the Funds in the Federated Fund Family; Executive Vice President, Federated Investors, Inc.; Director and Chief Executive Officer, Federated Securities Corp.

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Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years and Previous Position(s)
Brian P. Bouda Birth Date: February 28, 1947 CHIEF COMPLIANCE OFFICER AND SENIOR VICE PRESIDENT Officer since: August 2004; Retiring July 29, 2015	Principal Occupations: Senior Vice President and Chief Compliance Officer of the Federated Fund Family; Vice President and Chief Compliance Officer of Federated Investors, Inc. and Chief Compliance Officer of certain of its subsidiaries. Mr. Bouda joined Federated in 1999 and is a member of the American Bar Association and the State Bar Association of Wisconsin. Previous Positions: Served in Senior Management positions with a large regional banking organization.
Stephen Van Meter Birth Date: June 5, 1975 CHIEF COMPLIANCE OFFICER AND SENIOR VICE PRESIDENT Officer since: Effective July 30, 2015	Principal Occupations: Senior Vice President and Chief Compliance Officer of the Federated Fund Family; Vice President and Chief Compliance Officer of Federated Investors, Inc. and Chief Compliance Officer of certain of its subsidiaries. Mr. Van Meter joined Federated in October 2011. He holds FINRA licenses under Series 3, 7, 24 and 66. Previous Positions: Mr. Van Meter previously held the position of Compliance Operating Officer, Federated Investors, Inc. Prior to joining Federated, Mr. Van Meter served at the United States Securities and Exchange Commission in the positions of Senior Counsel, Office of Chief Counsel, Division of Investment Management and Senior Counsel, Division of Enforcement.
Deborah A. Cunningham Birth Date: September 15, 1959 Chief Investment Officer Officer since: May 2004	Principal Occupations: Deborah A. Cunningham was named Chief Investment Officer of Federated's money market products in 2004. She joined Federated in 1981 and has been a Senior Portfolio Manager since 1997 and an Executive Vice President of the Fund's Adviser since 2009. Ms. Cunningham has received the Chartered Financial Analyst designation and holds an M.S.B.A. in Finance from Robert Morris College.
Mary Jo Ochson Birth Date: September 12, 1953 Chief Investment Officer and Vice President Officer since: November 1998 Portfolio Manager since: August 1989	Principal Occupations: Mary Jo Ochson has been the Fund's Portfolio Manager since August 1989. Ms. Ochson was named Chief Investment Officer of Federated's tax-exempt fixed-income products in 2004 and Chief Investment Officer of Federated's Tax-Free Money Markets in 2010 and is a Vice President of the Corporation. She joined Federated in 1982 and has been a Senior Portfolio Manager and a Senior Vice President of the Fund's Adviser since 1996. Ms. Ochson has received the Chartered Financial Analyst designation and holds an M.B.A. in Finance from the University of Pittsburgh.

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Evaluation and Approval of Advisory Contract–May 2015

Federated Municipal Cash Series (the “Fund”)

Following a review and recommendation of approval by the Fund's independent directors, the Fund's Board reviewed and approved at its May 2015 meetings the Fund's investment advisory contract for an additional one-year term. The Board's decision regarding the contract reflects the exercise of its business judgment on whether to continue the existing arrangements.

In this connection, the Federated Funds' Board had previously appointed a Senior Officer, whose duties include specified responsibilities relating to the process by which advisory fees are to be charged to a Federated fund. The Senior Officer has the authority to retain consultants, experts, or staff as may be reasonably necessary to assist in the performance of his duties, reports directly to the Board, and may be terminated only with the approval of a majority of the independent members of the Board. The Senior Officer prepared and furnished to the Board an independent, written evaluation that covered topics discussed below (the “Evaluation”). The Board considered that Evaluation, along with other information, in deciding to approve the advisory contract.

The Board is also familiar with and considered judicial decisions concerning allegedly excessive investment advisory fees, which have indicated that the following factors may be relevant to an Adviser's fiduciary duty with respect to its receipt of compensation from a fund: the nature and quality of the services provided by the Adviser to a fund and its shareholders, including the performance and expenses of the fund and of comparable funds; the Adviser's cost of providing the services, including the profitability to the Adviser of providing advisory services to a fund; the extent to which the Adviser may realize “economies of scale” as a fund grows larger and, if such economies of scale exist, whether they have been shared with a fund and its shareholders or the family of funds; any “fall-out financial benefits” that accrue to the Adviser because of its relationship with a fund (including research services received from brokers that execute fund trades and any fees paid to affiliates of the Adviser for services rendered to a fund); comparative fee structures, including a comparison of fees paid to the Adviser with those paid by similar funds; and the extent of care, conscientiousness and independence with which the Board members perform their duties and their expertise, including whether they are fully informed about all facts the Board deems relevant to its consideration of the Adviser's services and fees. The Board noted that SEC disclosure requirements regarding the basis for the Board's approval of the Fund's advisory contract generally track the factors listed above. Consistent with these judicial decisions and SEC disclosure requirements, the Board also considered management fees

Annual Shareholder Report

26

charged to institutional and other clients of the Adviser for what might be viewed as like services. The Board was aware of these factors and was guided by them in its review of the Fund's advisory contract to the extent it considered them to be appropriate and relevant, as discussed further below.

The Board considered and weighed these circumstances in light of its substantial accumulated experience in governing the Fund and working with Federated on matters relating to the Federated funds, and was assisted in its deliberations by independent legal counsel. Throughout the year, and in connection with its May meetings, the Board requested and received substantial and detailed information about the Fund and the Federated organization that was in addition to the extensive materials that comprise and accompany the Senior Officer's Evaluation. Federated provided much of this information at each regular meeting of the Board, and furnished additional substantial information in connection with the May meeting at which the Board's formal review of the advisory contract occurred. At this May meeting, senior management of the Adviser also met with the independent directors and their counsel to discuss the materials presented and any other matters thought relevant by the Adviser or the directors. Between regularly scheduled meetings, the Board also received information on particular matters as the need arose. Thus, the Board's consideration of the advisory contract included review of the Senior Officer's Evaluation, accompanying data and additional information covering such matters as: the Adviser's investment philosophy, revenue, profitability, personnel and processes; investment and operating strategies; the Fund's short- and long-term performance (in absolute terms, both on a gross basis and net of expenses, as well as in relationship to its particular investment program and certain competitor or “peer group” funds and/or other benchmarks, as appropriate), and comments on the reasons for performance; the Fund's investment objectives; the Fund's expenses (including the advisory fee itself and the overall expense structure of the Fund, both in absolute terms and relative to similar and/or competing funds, with due regard for contractual or voluntary expense limitations); the use and allocation of brokerage commissions derived from trading the Fund's portfolio securities (if any); and the nature, quality and extent of the advisory and other services provided to the Fund by the Adviser and its affiliates. The Board also considered the preferences and expectations of Fund shareholders; the entrepreneurial risk assumed by the Adviser in sponsoring the funds; the continuing state of competition in the mutual fund industry and market practices; the range of comparable fees for similar funds in the mutual fund industry; the Fund's relationship to the Federated family of funds which include a comprehensive array of funds with different investment objectives, policies and strategies which are available for exchange without the incurrence of additional sales charges; compliance and audit reports concerning the Federated funds and the Federated companies that service them (including communications from regulatory agencies), as well as Federated's responses to any issues raised therein; and relevant developments in

Annual Shareholder Report

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the mutual fund industry and how the Federated funds and/or Federated are responding to them. The Board's evaluation process is evolutionary. The criteria considered and the emphasis placed on relevant criteria change in recognition of changing circumstances in the mutual fund marketplace.

While mindful that courts have cautioned against giving such comparisons too much weight, the Board has found the use of comparisons of the Fund's fees and expenses to other mutual funds with comparable investment programs to be relevant. In this regard, the Board was presented with, and considered, information regarding the contractual advisory fee rates, net advisory fee rates and total expense ratios relative to a fund's peers. The Board focused on comparisons with other similar mutual funds more heavily than non-mutual fund products or services because it is believed that they are more relevant. For example, other mutual funds are the products most like the Fund, they are readily available to Fund shareholders as alternative investment vehicles, and they are the type of investment vehicle in fact chosen and maintained by the Fund's investors. The range of their fees and expenses therefore appears to be a relevant indicator of what consumers have found to be reasonable in the precise marketplace in which the Fund competes.

It was noted in the materials for the Board meeting that for the period covered by the Evaluation, the Fund's investment advisory fee was waived in its entirety. The Board reviewed the contractual advisory fee rate, net advisory fee rate and other expenses of the Fund with the Adviser and noted the position of the Fund's fee rates relative to its peers. In this regard, the Board noted that the contractual advisory fee rate was above the median of the relevant peer group, but the Board noted that the investment advisory fee was waived in its entirety and that the overall expense structure of the Fund remained competitive.

By contrast, the Senior Officer has reviewed Federated's fees for providing advisory services to products outside the Federated family of funds (e.g., institutional and separate accounts and sub-adviser services). He concluded that mutual funds and institutional accounts are inherently different products. Those differences include, but are not limited to, different types of targeted investors; being subject to different laws and regulations; different legal structures; different average account sizes and portfolio management techniques made necessary by different cash flows and different associated costs; and the time spent by portfolio managers and their teams, funds financial services, legal, compliance and risk management in reviewing securities pricing, addressing different administrative responsibilities, addressing different degrees of risk associated with management and a variety of different costs. The Senior Officer did not consider these fee schedules to be determinative in judging the appropriateness of mutual fund advisory fees.

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The Fund's ability to deliver competitive performance when compared to its peer group was also deemed to be relevant by the Board as a useful indicator of how the Adviser is executing the Fund's investment program, which in turn was one of the Board's considerations in reaching a conclusion that the nature, extent, and quality of the Adviser's investment management services were such as to warrant continuation of the advisory contract.

The Senior Officer reviewed information compiled by Federated, using data supplied by independent fund ranking organizations, regarding the performance of, and fees charged by, other mutual funds, noting his view that comparisons to fund peer groups may be helpful, though not conclusive, in judging the reasonableness of the proposed fees. The Board considered, in evaluating such comparisons, that in some cases individual funds may exhibit significant and unique differences in their objectives and management techniques when compared to other funds within an industry peer group.

The Fund's performance fell below the median of the relevant peer group for the one-year period covered by the Evaluation. The Board discussed the Fund's performance with the Adviser and recognized the efforts being undertaken by the Adviser. The Board will continue to monitor these efforts and the performance of the Fund in the context of the other factors considered relevant by the Board.

The Board also received financial information about Federated, including information regarding the compensation and benefits Federated derived from its relationships with the Federated funds. This information covered not only the fees under the advisory contracts, but also fees received by Federated's subsidiaries for providing other services to the Federated funds under separate contracts (e.g., for serving as the Federated funds' administrator). The information also detailed any indirect benefit Federated may derive from its receipt of research services from brokers who execute Federated fund trades. In addition, the Board considered the fact that, in order for a fund to be competitive in the marketplace, Federated and its affiliates frequently waived fees and/or reimbursed expenses and have disclosed to fund investors and/or indicated to the Board their intention to do so in the future, where appropriate. Moreover, the Board receives regular reporting as to the institution, adjustment or elimination of these voluntary waivers.

In addition, over the past two years, following discussions regarding the Senior Officer's recommendations, Federated made meaningful reductions to the contractual advisory fees for several Funds. In May 2014, the Senior Officer recommended that Federated review the fee structures of its money market funds to determine whether it would be appropriate to consider alternative pricing structures. Federated has combined that review with its consideration of the re-structuring of its money market fund product line in response to the recently adopted amendments to Rule 2a-7 under the Investment Company Act of 1940, as amended (the “1940 Act”).

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29

At the Board meeting in May 2015, following previous recommendations of the Senior Officer, Federated proposed, and the Board approved, reductions in the contractual advisory fees of certain other Funds.

Federated furnished information, requested by the Senior Officer, that reported revenues on a fund-by-fund basis and made estimates of the allocation of expenses on a fund-by-fund basis, using allocation methodologies specified by the Senior Officer. The Senior Officer noted that, while these cost allocation reports apply consistent allocation processes, the inherent difficulties in allocating costs continues to cause the Senior Officer to question the precision of the process and to conclude that such reports may be unreliable, since a single change in an allocation estimate may dramatically alter the resulting estimate of cost and/or profitability of a fund and may produce unintended consequences. The allocation information, including the Senior Officer's view that fund-by-fund estimations may be unreliable, was considered in the analysis by the Board.

The Board and the Senior Officer also reviewed information compiled by Federated comparing profitability information for Federated to other publicly held fund management companies. In this regard, the Senior Officer concluded that Federated's profit margins did not appear to be excessive. The Senior Officer also noted that Federated appeared financially sound, with the resources to fulfill its obligations under its contracts with the Funds.

The Senior Officer's Evaluation also discussed the notion of possible realization of “economies of scale” as a fund grows larger. The Board considered in this regard that the Adviser has made significant and long-term investments in areas that support all of the Federated family of funds, such as personnel and processes for the portfolio management, shareholder services, compliance, internal audit, and risk management functions; and systems technology; and that the benefits of these efforts (as well as any economies of scale, should they exist) were likely to be enjoyed by the fund family as a whole. Federated, as it does throughout the year, and again in connection with the Board's review, furnished information relative to revenue sharing or adviser paid fees. Federated and the Senior Officer noted that this information should be viewed to determine if there was an incentive to either not apply breakpoints or to apply breakpoints at higher levels and should not be viewed to determining the appropriateness of advisory fees, because it would represent marketing and distribution expenses. Finally, the Board also noted the absence of any applicable regulatory or industry guidelines on this subject, which (as discussed in the Senior Officer's Evaluation) is compounded by the lack of any common industry practice or general pattern with respect to structuring fund advisory fees with “breakpoints” that serve to reduce the fee as the fund attains a certain size.

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The Senior Officer noted that, subject to the comments and recommendations made within his Evaluation, his observations and the information accompanying the Evaluation supported a finding by the Board that the management fees for each of the funds were reasonable. Under these circumstances, no objection was raised to the continuation of, the Fund's advisory contract.

In its decision to continue an existing investment advisory contract, the Board was mindful of the potential disruptions of the Fund's operations and various risks, uncertainties and other effects that could occur as a result of a decision to terminate or not renew an advisory contract. In particular, the Board recognized that many shareholders have invested in the Fund on the strength of the Adviser's industry standing and reputation and with the expectation that the Adviser will have a continuing role in providing advisory services to the Fund. Thus, the Board's approval of the advisory contract reflected the fact that it is the shareholders who have effectively selected the Adviser by virtue of having invested in the Fund. The Board concluded that, in light of the factors discussed above, including the nature, quality and scope of the services provided to the Fund by the Adviser and its affiliates, continuation of the advisory contract was appropriate.

The Board based its decision to approve the advisory contract on the totality of the circumstances and relevant factors and with a view to past and future long-term considerations. Not all of the factors and considerations identified above were necessarily relevant to the Fund, nor did the Board consider any one of them to be determinative. With respect to the factors that were relevant, the Board's decision to approve the contract reflects its determination that Federated's performance and actions provided a satisfactory basis to support the decision to continue the existing arrangements.

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Voting Proxies on Fund Portfolio Securities

A description of the policies and procedures that the Fund uses to determine how to vote proxies, if any, relating to securities held in the Fund's portfolio is available, without charge and upon request, by calling 1-800-341-7400. A report on “Form N-PX” of how the Fund voted any such proxies during the most recent 12-month period ended June 30 is available via the Proxy Voting Record (Form N-PX) link associated with the Fund and share class name at www.FederatedInvestors.com/FundInformation. Form N-PX filings are also available at the SEC's website at www.sec.gov.

Quarterly Portfolio Schedule

The Fund files with the SEC a complete schedule of its portfolio holdings, as of the close of the first and third quarters of its fiscal year, on “Form N-Q.” These filings are available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, DC. (Call 1-800-SEC-0330 for information on the operation of the Public Reference Room.) You may also access this information via the link to the Fund and share class name at www.FederatedInvestors.com/FundInformation.

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Mutual funds are not bank deposits or obligations, are not guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency. Investment in mutual funds involves investment risk, including the possible loss of principal. Although money market funds seek to maintain a stable net asset value of $1.00 per share, there is no assurance that they will be able to do so.

This Report is authorized for distribution to prospective investors only when preceded or accompanied by the Fund's Prospectus, which contains facts concerning its objective and policies, management fees, expenses and other information.

Federated Municipal Cash Series
Federated Investors Funds
4000 Ericsson Drive
Warrendale, PA 15086-7561

Contact us at FederatedInvestors.com
or call 1-800-341-7400.

Federated Securities Corp., Distributor

CUSIP 147551303

28565 (7/15)

Federated is a registered trademark of Federated Investors, Inc.
2015 ©Federated Investors, Inc.

Annual Shareholder Report

May 31, 2015

Ticker CTPXX

Federated Prime Cash Series

A Portfolio of Cash Trust Series, Inc.

Not FDIC Insured
May Lose Value

No Bank Guarantee

CONTENTS

Portfolio of Investments Summary Tables	1
Portfolio of Investments	2
Financial Highlights	10
Statement of Assets and Liabilities	11
Statement of Operations	12
Statement of Changes in Net Assets	13
Notes to Financial Statements	14
Report of Independent Registered Public Accounting Firm	21
Shareholder Expense Example	22
Board of Directors and Corporation Officers	24
Evaluation and Approval of Advisory Contract	30
Voting Proxies on Fund Portfolio Securities	36
Quarterly Portfolio Schedule	36

Portfolio of Investments Summary Tables (unaudited)

At May 31, 2015, the Fund's portfolio composition¹ was as follows:

Security Type	Percentage of Total Net Assets
Bank Instruments	29.2%
Commercial Paper and Notes	29.9%
Variable Rate Instruments	17.0%
Other Repurchase Agreements and Repurchase Agreements	23.9%
Other Assets and Liabilities—Net2	0.0%
TOTAL	100.0%

At May 31, 2015, the Fund's effective maturity schedule³ was as follows:

Securities with an Effective Maturity of:	Percentage of Total Net Assets
1-7 Days	38.3%
8-30 Days	30.7%
31-90 Days	21.7%
91-180 Days	6.4%
181 Days or more	2.9%
Other Assets and Liabilities—Net2	0.0%
TOTAL	100.0%

1	See the Fund's Prospectus and Statement of Additional Information for more complete information regarding these security types. With respect to this table, Commercial Paper and Notes includes asset-backed securities, a bank note, commercial paper, corporate bonds, a corporate note and a loan participation with interest rates that are fixed or reset periodically.
2	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.
3	Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940, which regulates money market mutual funds.

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1

Portfolio of Investments

May 31, 2015

Principal Amount			Value
		ASSET-BACKED SECURITIES—1.4%
		Finance - Automotive—1.1%
$8,183,875	1,2	ARI Fleet Lease Trust 2015-A, Class A1, 0.400%, 4/15/2016	$8,183,875
6,000,000	1,2	Drive Auto Receivables Trust 2015-B, Class A1, 0.460%, 6/15/2016	6,000,000
3,782,315		SMART ABS Series 2015-1US Trust, Class A1, 0.400%, 3/14/2016	3,782,315
14,102,961	1,2	Westlake Automobile Receivables Trust 2015-1, Class A1, 0.400%, 3/15/2016	14,102,961
		TOTAL	32,069,151
		Finance - Equipment—0.3%
4,593,561	1	Leaf Equipment Contract Backed Notes, Series 2015-1, Class A1, 0.500%, 5/16/2016	4,593,561
2,621,713	1,2	Macquarie Equipment Funding Trust 2014-A, Class A1, 0.260%, 9/21/2015	2,621,713
		TOTAL	7,215,274
		TOTAL ASSET-BACKED SECURITIES	39,284,425
		BANK NOTE—1.7%
		Finance - Banking—1.7%
50,000,000		Bank of America N.A., 0.260%, 7/16/2015	50,000,000
		CERTIFICATES OF DEPOSIT—17.0%
		Finance - Banking—17.0%
40,000,000		ABN Amro Bank NV, 0.290%, 8/17/2015	39,975,207
10,000,000		Bank of Montreal, 0.346%, 6/23/2015	10,000,000
25,000,000		Bank of Nova Scotia, Toronto, 0.340%, 11/24/2015	25,000,000
129,000,000		Bank of Tokyo-Mitsubishi UFJ Ltd., 0.250% - 0.280%, 6/2/2015 - 9/8/2015	129,000,000
25,000,000		Credit Agricole Corporate and Investment Bank, 0.250%, 8/6/2015	25,000,000
75,000,000		DZ Bank AG Deutsche Zentral-Genossenschaftbank, 0.250% - 0.280%, 8/4/2015 - 9/1/2015	75,000,000
54,000,000		Mizuho Bank Ltd., 0.260%, 7/2/2015 - 7/21/2015	54,000,000
10,000,000		Natixis, 0.250%, 6/22/2015	10,000,000
60,000,000		Standard Chartered Bank PLC, 0.240% - 0.270%, 6/11/2015 - 8/27/2015	60,000,000
59,000,000		Sumitomo Mitsui Banking Corp., 0.270%, 6/8/2015 - 7/15/2015	59,000,000
		TOTAL CERTIFICATES OF DEPOSIT	486,975,207
		COMMERCIAL PAPER—23.8%3
		Aerospace/Auto—1.4%
14,020,000	1,2	ERAC USA Finance LLC, (GTD by Enterprise Holdings, Inc.), 0.450% - 0.500%, 6/19/2015 - 6/25/2015	14,015,879

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2

Principal Amount			Value
		COMMERCIAL PAPER—continued3
		Aerospace/Auto—continued
$25,000,000		Toyota Motor Credit Corp., (Toyota Motor Corp. SA), 0.260%, 6/8/2015	$24,998,736
		TOTAL	39,014,615
		Chemicals—0.5%
14,540,000		PPG Industries, Inc., 0.430% - 0.450%, 6/4/2015 - 6/26/2015	14,538,470
		Consumer Products—1.2%
5,215,000	1,2	Diageo Capital PLC, (GTD by Diageo PLC), 0.400%, 6/4/2015	5,214,826
28,500,000		Unilever N.V., 0.320%, 8/17/2015	28,480,523
		TOTAL	33,695,349
		Container\Packaging—0.1%
2,000,000	1,2	Bemis Co., Inc., 0.460%, 6/9/2015	1,999,796
		Electric Power—0.2%
7,150,000		Virginia Electric & Power Co., 0.430%, 6/1/2015	7,150,000
		Electrical Equipment—0.3%
9,990,000	1,2	Eaton Corp., (GTD by Eaton Corp. PLC), 0.450%, 6/29/2015	9,986,504
		Finance - Banking—8.6%
25,000,000		ING (U.S.) Funding LLC, 0.250%, 6/2/2015	24,999,826
41,000,000	1,2	J.P. Morgan Securities LLC, 0.331% - 0.401%, 6/15/2015 - 9/29/2015	40,963,408
40,000,000	1,2	LMA-Americas LLC, 0.260%, 8/20/2015	39,976,889
35,000,000	1,2	Matchpoint Master Trust, 0.250%, 6/24/2015	34,994,410
20,000,000	1,2	Societe Generale, Paris, 0.250%, 6/16/2015	19,997,917
85,000,000		Standard Chartered Bank PLC, 0.240% - 0.250%, 6/18/2015 - 6/25/2015	84,988,497
		TOTAL	245,920,947
		Finance - Commercial—3.5%
25,000,000	1,2	Alpine Securitization Corp., 0.250%, 7/16/2015	24,992,187
25,000,000	1,2	Atlantic Asset Securitization LLC, 0.250%, 8/5/2015	24,988,715
20,000,000	1,2	Fairway Finance Co. LLC, 0.280%, 10/13/2015	19,979,156
30,000,000	1,2	Versailles Commercial Paper LLC, 0.270%, 9/4/2015	29,978,625
		TOTAL	99,938,683
		Finance - Retail—5.6%
40,000,000		American Express Credit Corp., 0.290%, 8/24/2015	39,972,934
35,000,000	1,2	Chariot Funding LLC, 0.401% - 0.421%, 1/28/2016 - 2/16/2016	34,902,722
85,000,000	1,2	Starbird Funding Corp., 0.250%, 6/8/2015	84,995,868
		TOTAL	159,871,524
		Food & Beverage—0.4%
10,000,000	1,2	Agrium, Inc., 0.450% - 0.480%, 6/4/2015 - 6/26/2015	9,997,794
		Oil & Oil Finance—0.7%
480,000	1,2	Devon Energy Corp., 0.410%, 6/19/2015	479,901

Annual Shareholder Report

3

Principal Amount			Value
		COMMERCIAL PAPER—continued3
		Oil & Oil Finance—continued
$6,010,000	1,2	Enbridge (U.S.) Inc., (GTD by Enbridge, Inc.), 0.630%, 6/17/2015	$6,008,317
14,500,000		Motiva Enterprises LLC, 0.450% - 0.460%, 6/4/2015 - 6/8/2015	14,499,093
		TOTAL	20,987,311
		Sovereign—1.2%
35,000,000	1,2	Caisse des Depots et Consignations (CDC), 0.275%, 7/8/2015	34,990,108
		Telecommunications—0.1%
3,100,000	1,2	NBC Universal Enterprise, Inc., (GTD by Comcast Corp.), 0.450%, 6/10/2015	3,099,651
		TOTAL COMMERCIAL PAPER	681,190,752
		CORPORATE BONDS—1.9%
		Finance - Banking—1.0%
6,600,000		Bank of America Corp., 4.750%, 8/1/2015	6,643,561
10,970,000		Citigroup, Inc., 2.250%, 8/7/2015	11,002,747
10,000,000		Wells Fargo & Co., 1.500%, 7/1/2015	10,009,874
		TOTAL	27,656,182
		Finance - Commercial—0.2%
1,875,000		General Electric Capital Corp., 2.250%, 11/9/2015	1,890,189
1,000,000		General Electric Capital Corp., 3.500%, 6/29/2015	1,002,361
4,540,000		General Electric Capital Corp., 5.000%, 1/8/2016	4,662,819
		TOTAL	7,555,369
		Finance - Retail—0.7%
5,941,000		American Express Credit Corp., 1.750%, 6/12/2015	5,943,376
13,700,000		American Express Credit Corp., 2.750%, 9/15/2015	13,791,789
		TOTAL	19,735,165
		TOTAL CORPORATE BONDS	54,946,716
		CORPORATE NOTE—0.2%
		Insurance—0.2%
7,100,000	1,2	Metropolitan Life Global Funding I, 1.700%, 6/29/2015	7,107,230
		LOAN PARTICIPATION—0.9%
		Chemicals—0.9%
25,000,000		DuPont Teijin Films U.S. L.P., (GTD by DuPont (E.I.) de Nemours & Co.), 0.400%, 6/29/2015	25,000,000
		NOTES - VARIABLE—29.2%4
		Aerospace/Auto—1.4%
16,000,000		BMW US Capital LLC, (GTD by Bayerische Motoren Werke AG), 0.394%, 7/17/2015	16,000,000
15,000,000		BMW US Capital LLC, (GTD by Bayerische Motoren Werke AG), 0.400%, 8/5/2015	15,000,000

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Principal Amount			Value
		NOTES - VARIABLE—continued4
		Aerospace/Auto—continued
$10,000,000		Toyota Motor Credit Corp., (Toyota Motor Corp. SA), 0.279%, 7/29/2015	$10,000,000
		TOTAL	41,000,000
		Finance - Automotive—0.2%
6,110,107	1	Drive Auto Receivables Trust 2015-A, Class A1, 0.470%, 6/15/2015	6,110,107
		Finance - Banking—25.5%
25,000,000		BMO Harris Bank, N.A., 0.285%, 6/25/2015	25,000,000
50,000,000		Bank of Montreal, 0.262%, 6/3/2015	50,000,000
25,000,000		Bank of Montreal, 0.292%, 6/11/2015	25,000,000
14,000,000		Bank of Montreal, 0.333%, 6/18/2015	14,000,000
1,050,000		6380 Brackbill Associates LP, (Series 2000), (Manufacturers & Traders Trust Co., Buffalo, NY LOC), 0.540%, 6/5/2015	1,050,000
30,000,000	1,2	Bedford Row Funding Corp., (GTD by Royal Bank of Canada, Montreal), 0.292%, 6/9/2015	30,000,000
10,000,000	1,2	Bedford Row Funding Corp., (GTD by Royal Bank of Canada, Montreal), 0.309%, 7/28/2015	10,000,000
5,000,000	1,2	Bedford Row Funding Corp., (GTD by Royal Bank of Canada, Montreal), 0.317%, 6/16/2015	5,000,000
9,000,000	1,2	BlackRock Municipal Income Quality Trust, VMTP Preferred Shares (Series T0009), 0.200%, 6/1/2015	9,000,000
13,480,000		Carew Realty, Inc., (Series 2012), (Fifth Third Bank, Cincinnati LOC), 0.240%, 6/4/2015	13,480,000
70,500,000	1,2	Firstmac Mortgage Funding Trust No.4 Series 1A-2014, Class A2A, (GTD by National Australia Bank Ltd., Melbourne), 0.535%, 6/26/2015	70,502,984
3,050,000		Gannett Fleming, Inc., (Series 2001), (Manufacturers & Traders Trust Co., Buffalo, NY LOC), 0.540%, 6/5/2015	3,050,000
1,375,000		Graywood Farms LLC, (Manufacturers & Traders Trust Co., Buffalo, NY LOC), 0.540%, 6/5/2015	1,375,000
56,150,000	1,2	Illinois State, Taxable PUTTERs (Series SGT01), 0.190%, 6/1/2015	56,150,000
25,000,000		JPMorgan Chase Bank, N.A., 0.325%, 6/22/2015	25,000,000
19,455,000		Kansas City, MO Tax Increment Financing Commission, Blue Ridge Mall Redevelopment Project (Series 2005), (BMO Harris Bank, N.A. LOC), 0.150%, 6/3/2015	19,455,000
50,000,000		Maryland State Economic Development Corp., (Series 2001A Human Genome Sciences), (Manufacturers & Traders Trust Co., Buffalo, NY LOC), 0.530%, 6/2/2015	50,000,000
50,000,000		National Australia Bank Ltd., Melbourne, 0.263%, 6/18/2015	50,000,000
39,100,000		Natixis, 0.302%, 6/10/2015	39,100,000
5,000,000	1,2	New Jersey State, PUTTERs (Series 4459), (JPMorgan Chase Bank, N.A. LOC), 0.120%, 6/1/2015	5,000,000
25,000,000		Royal Bank of Canada, Montreal, 0.300%, 6/8/2015	25,000,000
30,000,000		Royal Bank of Canada, Montreal, 0.324%, 7/9/2015	30,000,000

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5

Principal Amount			Value
		NOTES - VARIABLE—continued4
		Finance - Banking—continued
$20,000,000		Royal Bank of Canada, Montreal, 0.391%, 7/6/2015	$20,000,000
25,000,000		State Street Bank and Trust Co., 0.266%, 6/15/2015	25,000,000
15,000,000		State Street Bank and Trust Co., 0.324%, 7/1/2015	15,000,000
30,000,000		Sumitomo Mitsui Banking Corp., 0.282%, 6/10/2015	30,000,000
2,500,000		Sun Valley, Inc., (Wells Fargo Bank, N.A. LOC), 0.230%, 6/5/2015	2,500,000
25,000,000		Toronto Dominion Bank, 0.271%, 6/4/2015	25,000,000
20,000,000		Toronto Dominion Bank, 0.305%, 7/15/2015	20,000,000
25,000,000		Toronto Dominion Bank, 0.337%, 6/22/2015	25,000,000
8,500,000		Village Green Finance Co. LLC, (Series 1997), (Wells Fargo Bank, N.A. LOC), 0.180%, 6/3/2015	8,500,000
		TOTAL	728,162,984
		Finance - Commercial—0.4%
300,000		General Electric Capital Corp., 0.461%, 7/6/2015	300,143
11,730,000	1,2	Mountain Creek Properties LLC, (General Electric Capital Corp. LOC), 0.130%, 6/4/2015	11,730,000
		TOTAL	12,030,143
		Finance - Retail—1.3%
37,000,000	1,2	Barton Capital LLC, 0.282%, 11/5/2015	37,000,000
		Government Agency—0.4%
9,920,000		Capital Trust Agency, FL, (FNMA LOC), 0.140%, 6/4/2015	9,920,000
		TOTAL NOTES—VARIABLE	834,223,234
		OTHER REPURCHASE AGREEMENTS—17.9%
		Finance - Banking—17.9%
27,500,000		Citigroup Global Markets, Inc., 0.568% - 0.791%, 6/1/2015 - 7/21/2015, interest in a $160,000,000 collateralized loan agreement, dated 5/22/2015-5/29/2015, in which American depositary receipts, asset-backed securities, collateralized mortgage obligations, common stock and a convertible bond with a market value of $163,222,366 have been received as collateral and held with BNY Mellon as tri-party agent.	27,500,000
20,000,000		Credit Suisse Securities (USA) LLC, 0.639%, 6/4/2015, interest in a $300,000,000 collateralized loan agreement, dated 4/21/2015 in which collateralized mortgage obligations with a market value of $306,204,999 have been received as collateral and held with JPMorgan Chase as tri-party agent.	20,000,000
12,500,000		Goldman Sachs & Co., 0.233%, 6/3/2015, interest in a $38,500,000 collateralized loan agreement, dated 5/27/2015 in which asset-backed securities, a collateralized mortgage obligation and U.S. government security with a market value of $39,271,475 have been received as collateral and held with JPMorgan Chase as tri-party agent.	12,500,000

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Principal Amount		Value
	OTHER REPURCHASE AGREEMENTS—continued
	Finance - Banking—continued
$65,000,000	J.P. Morgan Securities LLC, 0.355% - 0.365%, 6/8/2015 - 7/1/2015, interest in a $650,000,000 collateralized loan agreement, dated 3/10/2015 - 4/2/2015, in which asset-backed securities and corporate bonds with a market value of $663,468,909 have been received as collateral and held with JPMorgan Chase as tri-party agent.	$65,000,000
123,000,000	Merrill Lynch, Pierce, Fenner & Smith, Inc., 0.365% - 0.689%, 6/1/2015 - 8/24/2015, interest in a $305,000,000 collateralized loan agreement, dated 5/26/2015-5/29/2015, in which asset-backed securities, collateralized mortgage obligations, corporate bonds and a medium-term note with a market value of $311,118,089 have been received as collateral and held with BNY Mellon as tri-party agent.	123,000,000
15,000,000	Mitsubishi UFJ Securities (USA), Inc., 0.253%, 6/17/2015, interest in a $200,000,000 collateralized loan agreement, dated 5/14/2015 in which asset-backed securities, common stock, corporate bonds, exchange-traded funds and medium-term notes with a market value of $204,025,505 have been received as collateral and held with JPMorgan Chase as tri-party agent.	15,000,000
63,000,000	Mizuho Securities USA, Inc., 0.456%, 6/10/2015, interest in a $110,000,000 collateralized loan agreement, dated 5/27/2015, in which asset-backed securities, commercial paper, corporate bonds, medium-term notes and U.S. government securities with a market value of $112,207,013 have been received as collateral and held with BNY Mellon as tri-party agent.	63,000,000
25,000,000	Pershing LLC, 0.365%, 6/1/2015, interest in a $200,000,000 collateralized loan agreement, dated 5/29/2015, in which asset-backed securities, commercial paper, corporate bonds, medium-term notes and municipal bonds with a market value of $204,019,684 have been received as collateral and held with BNY Mellon as tri-party agent.	25,000,000
20,000,000	RBC Capital Markets, LLC, 0.294%, 6/11/2015, interest in a $300,000,000 collateralized loan agreement, dated 3/15/2015, in which corporate bonds and medium-term notes with a market value of $306,197,201 have been received as collateral and held with BNY Mellon as tri-party agent.	20,000,000
140,000,000	Wells Fargo Securities LLC, 0.456%, 7/9/2015 - 7/27/2015, interest in a $870,000,000 collateralized loan agreement, dated 4/9/2015–4/27/2015, in which asset-backed securities, collateralized mortgage obligations, convertible bonds, exchange-traded funds and unit investment trusts with a market value of $887,891,817 have been received as collateral and held with BNY Mellon as tri-party agent.	140,000,000
	TOTAL OTHER REPURCHASE AGREEMENTS	511,000,000

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7

Principal Amount		Value
	REPURCHASE AGREEMENTS—6.0%
	Finance - Banking—6.0%
$20,281,000	Interest in $3,500,000,000 joint repurchase agreement 0.09%, dated 5/29/2015 under which Credit Agricole CIB New York will repurchase securities provided as collateral for $3,500,026,250 on 6/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 5/15/2045 and the market value of those underlying securities was $3,570,026,786.	$20,281,000
150,000,000	Interest in $2,500,000,000 joint repurchase agreement 0.11%, dated 5/29/2015 under which Natixis Financial Products LLC will repurchase securities provided as collateral for $2,500,022,917 on 6/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency and U.S. Treasury securities with various maturities to 6/15/2055 and the market value of those underlying securities was $2,556,477,894.	150,000,000
	TOTAL REPURCHASE AGREEMENTS	170,281,000
	TOTAL INVESTMENTS—100.0% (AT AMORTIZED COST)5	2,860,008,564
	OTHER ASSETS AND LIABILITIES - NET—0.0%6	842,173
	TOTAL NET ASSETS—100%	$2,860,850,737

1	Denotes a restricted security that either: (a) cannot be offered for public sale without first being registered, or being able to take advantage of an exemption from registration, under the Securities Act of 1933; or (b) is subject to a contractual restriction on public sales. At May 31, 2015, these restricted securities amounted to $724,665,104, which represented 25.3% of total net assets.
2	Denotes a restricted security that may be resold without restriction to “qualified institutional buyers” as defined in Rule 144A under the Securities Act of 1933 and that the Fund has determined to be liquid under criteria established by the Fund's Board of Directors (the “Directors”). At May 31, 2015, these liquid restricted securities amounted to $713,961,436, which represented 25.0% of total net assets.
3	Discount rate at time of purchase.
4	Denotes a variable rate security with current rate and next reset date shown.
5	Also represents cost for federal tax purposes.
6	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.

Note: The categories of investments are shown as a percentage of total net assets at May 31, 2015.

Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below:

Level 1—quoted prices in active markets for identical securities.

Level 2—other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.). Also includes securities valued at amortized cost.

Level 3—significant unobservable inputs (including the Fund's own assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities.

Annual Shareholder Report

8

As of May 31, 2015, all investments of the Fund are valued at amortized cost, which is considered a Level 2 input, in valuing the Fund's assets.

The following acronyms are used throughout this portfolio:

FNMA	—Federal National Mortgage Association
GTD	—Guaranteed
LOC	—Letter of Credit
PUTTERs	—Puttable Tax-Exempt Receipts
VMTP	—Variable Municipal Term Preferred

See Notes which are an integral part of the Financial Statements

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9

Financial Highlights

(For a Share Outstanding Throughout Each Period)

Year Ended May 31	2015	2014	2013	2012	2011
Net Asset Value, Beginning of Period	$1.00	$1.00	$1.00	$1.00	$1.00
Income From Investment Operations:
Net investment income	0.0001	0.0001	0.0001	0.0001	0.0001
Net realized gain (loss) on investments	0.0001	0.0001	0.0001	(0.000)1	0.0001
TOTAL FROM INVESTMENT OPERATIONS	0.0001	0.0001	0.0001	0.0001	0.0001
Less Distributions:
Distributions from net investment income	(0.000)1	(0.000)1	(0.000)1	(0.000)1	(0.000)1
Distributions from net realized gain on investments	(0.000)1	(0.000)1	(0.000)1	(0.000)1	(0.000)1
TOTAL DISTRIBUTIONS	(0.000)1	(0.000)1	(0.000)1	(0.000)1	(0.000)1
Net Asset Value, End of Period	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return2	0.01%	0.01%	0.01%	0.01%	0.01%
Ratios to Average Net Assets:
Net expenses	0.27%	0.27%	0.35%	0.38%	0.43%
Net investment income	0.01%	0.01%	0.01%	0.01%	0.01%
Expense waiver/reimbursement3	0.80%	0.82%	0.73%	0.70%	0.65%
Supplemental Data:
Net assets, end of period (000 omitted)	$2,860,851	$2,926,756	$2,955,903	$2,966,768	$4,559,876

1	Represents less than $0.001.
2	Based on net asset value.
3	This expense decrease is reflected in both the net expense and the net investment income ratios shown above.

See Notes which are an integral part of the Financial Statements

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Statement of Assets and Liabilities

May 31, 2015

Assets:
Investment in repurchase agreements and other repurchase agreements	$681,281,000
Investment in securities	2,178,727,564
Total investment in securities, at amortized cost and fair value		$2,860,008,564
Cash		1,618
Income receivable		1,192,795
Receivable for shares sold		89,142
TOTAL ASSETS		2,861,292,119
Liabilities:
Payable for shares redeemed	26,391
Payable to adviser (Note 5)	8,929
Payable for custodian fees	17,262
Payable for transfer agent fee	323,035
Payable for Directors'/Trustees' fees (Note 5)	1,707
Payable for portfolio accounting fees	27,622
Payable for printing and postage	21,124
Accrued expenses (Note 5)	15,312
TOTAL LIABILITIES		441,382
Net assets for 2,860,840,083 shares outstanding		$2,860,850,737
Net Assets Consist of:
Paid-in capital		$2,860,840,083
Accumulated net realized gain on investments		10,573
Undistributed net investment income		81
TOTAL NET ASSETS		$2,860,850,737
Net Asset Value, Offering Price and Redemption Proceeds Per Share:
$2,860,850,737 ÷ 2,860,840,083 shares outstanding, $0.001 par value, 12,500,000,000 shares authorized		$1.00

See Notes which are an integral part of the Financial Statements

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Statement of Operations

Year Ended May 31, 2015

Investment Income:
Interest			$8,455,784
Expenses:
Investment adviser fee (Note 5)		$14,867,380
Administrative fee (Note 5)		2,326,497
Custodian fees		123,773
Transfer agent fee		3,221,858
Directors'/Trustees' fees (Note 5)		19,932
Auditing fees		21,250
Legal fees		11,224
Portfolio accounting fees		167,510
Distribution services fee (Note 5)		2,973,476
Other service fees (Note 2)		7,433,690
Share registration costs		279,534
Printing and postage		362,769
Taxes		191,872
Miscellaneous (Note 5)		22,214
TOTAL EXPENSES		32,022,979
Waivers and Reimbursement:
Waiver of investment adviser fee (Note 5)	$(13,456,282)
Waivers/reimbursement of other operating expenses (Notes 2 and 5)	(10,407,166)
TOTAL WAIVERS AND REIMBURSEMENT		(23,863,448)
Net expenses			8,159,531
Net investment income			296,253
Net realized gain on investments			10,695
Change in net assets resulting from operations			$306,948

See Notes which are an integral part of the Financial Statements

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Statement of Changes in Net Assets

Year Ended May 31	2015	2014
Increase (Decrease) in Net Assets
Operations:
Net investment income	$296,253	$295,617
Net realized gain on investments	10,695	12,611
CHANGE IN NET ASSETS RESULTING FROM OPERATIONS	306,948	308,228
Distributions to Shareholders:
Distributions from net investment income	(296,183)	(295,534)
Distributions from net realized gain on investments	(8,673)	(11,055)
CHANGE IN NET ASSETS RESULTING FROM DISTRIBUTIONS TO SHAREHOLDERS	(304,856)	(306,589)
Share Transactions:
Proceeds from sale of shares	2,992,899,413	3,070,879,415
Net asset value of shares issued to shareholders in payment of distributions declared	303,734	305,010
Cost of shares redeemed	(3,059,110,597)	(3,100,333,188)
CHANGE IN NET ASSETS RESULTING FROM SHARE TRANSACTIONS	(65,907,450)	(29,148,763)
Change in net assets	(65,905,358)	(29,147,124)
Net Assets:
Beginning of period	2,926,756,095	2,955,903,219
End of period (including undistributed net investment income of $81 and $11, respectively)	$2,860,850,737	$2,926,756,095

See Notes which are an integral part of the Financial Statements

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Notes to Financial Statements

May 31, 2015

1. ORGANIZATION

Cash Trust Series, Inc. (the “Corporation”) is registered under the Investment Company Act of 1940, as amended (the “Act”), as a diversified open-end management investment company. The Corporation consists of four portfolios. The financial statements included herein are only those of Federated Prime Cash Series (the “Fund”), a diversified portfolio. The financial statements of the other portfolios are presented separately. The assets of each portfolio are segregated and a shareholder's interest is limited to the portfolio in which shares are held. Each portfolio pays its own expenses. The investment objective of the Fund is current income consistent with stability of principal and liquidity.

2. SIGNIFICANT ACCOUNTING POLICIES

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. These policies are in conformity with U.S. generally accepted accounting principles (GAAP).

Investment Valuation

Securities are valued at amortized cost. Under the amortized cost valuation method, an investment is valued initially at its cost as determined in accordance with GAAP. The Fund then adjusts the amount of interest income accrued each day over the term of the investment to account for any difference between the initial cost of the investment and the amount payable at its maturity. If amortized cost is determined not to approximate fair value, the value of the portfolio securities will be determined in accordance with the procedures described below.

The Directors have ultimate responsibility for determining the fair value of investments. The Directors have appointed a Valuation Committee (“Valuation Committee”) comprised of officers of the Fund, Federated Investment Management Company (“Adviser”) and certain of the Adviser's affiliated companies to assist in determining fair value of securities and in overseeing the comparison of amortized cost to market-based value. The Directors have also authorized the use of pricing services recommended by the Valuation Committee to provide fair value evaluations of the current value of certain investments for purposes of monitoring the relationship of market-based value and amortized cost. The Valuation Committee employs various methods for reviewing third-party pricing-service evaluations including periodic reviews of third-party pricing services' policies, procedures and valuation methods (including key inputs and assumptions), and review of price challenges by the Adviser based on recent market activity. In the event that market quotations and price evaluations are not available for an investment, the Valuation Committee determines the fair value of the investment in accordance with procedures adopted by the Directors. The Directors periodically review and approve the fair valuations made by the Valuation Committee and any changes made to the procedures.

Repurchase Agreements

The Fund may invest in repurchase agreements for short-term liquidity purposes. It is the policy of the Fund to require the other party to a repurchase agreement to transfer to the Fund's custodian or sub-custodian eligible securities or cash with a market value (after transaction costs) at least equal to the repurchase price to be paid under the repurchase

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14

agreement. The eligible securities are transferred to accounts with the custodian or sub-custodian in which the Fund holds a “securities entitlement” and exercises “control” as those terms are defined in the Uniform Commercial Code. The Fund has established procedures for monitoring the market value of the transferred securities and requiring the transfer of additional eligible securities if necessary to equal at least the repurchase price. These procedures also allow the other party to require securities to be transferred from the account to the extent that their market value exceeds the repurchase price or in exchange for other eligible securities of equivalent market value.

The insolvency of the other party or other failure to repurchase the securities may delay the disposition of the underlying securities or cause the Fund to receive less than the full repurchase price. Under the terms of the repurchase agreement, any amounts received by the Fund in excess of the repurchase price and related transaction costs must be remitted to the other party.

The Fund may enter into repurchase agreements in which eligible securities are transferred into joint trading accounts maintained by the custodian or sub-custodian for investment companies and other clients advised by the Fund's Adviser and its affiliates. The Fund will participate on a pro rata basis with the other investment companies and clients in its share of the securities transferred under such repurchase agreements and in its share of proceeds from any repurchase or other disposition of such securities.

Repurchase agreements are subject to Master Netting Agreements which are agreements between the Fund and its counterparties that provide for the net settlement of all transactions and collateral with the Fund, through a single payment, in the event of default or termination. Amounts presented on the Portfolio of Investments and Statement of Assets and Liabilities are not net settlement amounts but gross. As indicated above, the cash or securities to be repurchased, as shown on the Portfolio of Investments, exceeds the repurchase price to be paid under the agreement reducing the net settlement amount to zero.

Investment Income, Gains and Losses, Expenses and Distributions

Investment transactions are accounted for on a trade-date basis. Realized gains and losses from investment transactions are recorded on an identified-cost basis. Interest income and expenses are accrued daily. Distributions to shareholders are recorded on the ex-dividend date. Distributions of net investment income are declared daily and paid monthly.

Other Service Fees

The Fund may pay other service fees up to 0.25% of the average daily net assets of the Fund's Shares to unaffiliated financial intermediaries or to Federated Shareholder Services Company (FSSC) for providing services to shareholders and maintaining shareholder accounts. Subject to the terms described in the Expense Limitation note, FSSC may voluntarily reimburse the Fund for other service fees. For the year ended May 31, 2015, FSSC voluntarily reimbursed $954 of other service fees. In addition, for the year ended May 31, 2015, unaffiliated third-party financial intermediaries waived $7,432,736 of other service fees. This waiver can be modified or terminated at any time.

Premium and Discount Amortization

All premiums and discounts are amortized/accreted using the effective-interest-rate method.

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Federal Taxes

It is the Fund's policy to comply with the Subchapter M provision of the Internal Revenue Code and to distribute to shareholders each year substantially all of its income. Accordingly, no provision for federal income tax is necessary. As of and during the year ended May 31, 2015, the Fund did not have a liability for any uncertain tax positions. The Fund recognizes interest and penalties, if any, related to tax liabilities as income tax expense in the Statement of Operations. As of May 31, 2015, tax years 2012 through 2015 remain subject to examination by the Fund's major tax jurisdictions, which include the United States of America, the state of Maryland and the Commonwealth of Pennsylvania.

Other Taxes

As an open-end management investment company incorporated in the state of Maryland but domiciled in the Commonwealth of Pennsylvania, the Fund is subject to the Pennsylvania Franchise Tax. This franchise tax is assessed annually on the value of the Fund, as represented by average net assets for the tax year.

When-Issued and Delayed-Delivery Transactions

The Fund may engage in when-issued or delayed-delivery transactions. The Fund records when-issued securities on the trade date and maintains security positions such that sufficient liquid assets will be available to make payment for the securities purchased. Securities purchased on a when-issued or delayed-delivery basis are marked to market daily and begin earning interest on the settlement date. Losses may occur on these transactions due to changes in market conditions or the failure of counterparties to perform under the contract.

Restricted Securities

The Fund may purchase securities which are considered restricted. Restricted securities are securities that either: (a) cannot be offered for public sale without first being registered, or being able to take advantage of an exemption from registration, under the Securities Act of 1933; or (b) are subject to contractual restrictions on public sales. In some cases, when a security cannot be offered for public sale without first being registered, the issuer of the restricted security has agreed to register such securities for resale, at the issuer's expense, either upon demand by the Fund or in connection with another registered offering of the securities. Many such restricted securities may be resold in the secondary market in transactions exempt from registration. Restricted securities may be determined to be liquid under criteria established by the Directors. The Fund will not incur any registration costs upon such resales. Restricted securities are valued at amortized cost in accordance with Rule 2a-7 under the Act.

Additional information on restricted securities, excluding securities purchased under Rule 144A that have been deemed liquid by the Trustees, if applicable, held at May 31, 2015, is as follows:

Security	Acquisition Date	Cost	Market Value
Drive Auto Receivables Trust 2015-A, Class A1, 0.470%, 6/15/2015	5/20/2015	$6,000,000	$6,110,107
Leaf Equipment Contract Backed Notes, Series 2015-1, Class A1, 0.500%, 5/16/2016	4/23/2015	$4,593,561	$4,593,561

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Other

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, expenses and revenues reported in the financial statements. Actual results could differ from those estimated. The Fund applies Investment Company accounting and reporting guidance.

3. CAPITAL STOCK

The following table summarizes capital stock activity:

Year Ended May 31	2015	2014
Shares sold	2,992,899,413	3,070,879,415
Shares issued to shareholders in payment of distributions declared	303,734	305,010
Shares redeemed	(3,059,110,597)	(3,100,333,188)
NET CHANGE RESULTING FROM FUND SHARE TRANSACTIONS	(65,907,450)	(29,148,763)

4. FEDERAL TAX INFORMATION

The tax character of distributions as reported on the Statement of Changes in Net Assets for the years ended May 31, 2015 and 2014, was as follows:

	2015	2014
Ordinary income1	$304,856	$306,589

1 For tax purposes, short-term capital gain distributions are considered as ordinary income distributions.

As of May 31, 2015, the components of distributable earnings on a tax basis were as follows:

Undistributed ordinary income² $10,654

2 For tax purposes, short-term capital gains are considered ordinary income in determining distributable earnings.

5. INVESTMENT ADVISER FEE AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Adviser Fee

The advisory agreement between the Fund and the Adviser provides for an annual fee equal to 0.50% of the Fund's average daily net assets. Subject to the terms described in the Expense Limitation note, the Adviser may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2015, the Adviser voluntarily waived $13,456,282 of its fee.

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Administrative Fee

Federated Administrative Services (FAS), under the Administrative Services Agreement, provides the Fund with administrative personnel and services. For purposes of determining the appropriate rate breakpoint, “Investment Complex” is defined as all of the Federated Funds subject to a fee under the Administrative Services Agreement. The fee paid to FAS is based on the average daily net assets of the Investment Complex as specified below, plus certain out-of-pocket expenses:

Administrative Fee	Average Daily Net Assets of the Investment Complex
0.150%	on the first $5 billion
0.125%	on the next $5 billion
0.100%	on the next $10 billion
0.075%	on assets in excess of $20 billion

Subject to the terms described in the Expense Limitation note, FAS may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2015, the annualized fee paid to FAS was 0.078% of average daily net assets of the Fund.

Distribution Services Fee

The Fund has adopted a Distribution Plan (the “Plan”) pursuant to Rule 12b-1 under the Act. Under the terms of the Plan, the Fund will reimburse Federated Securities Corp. (FSC), the principal distributor, from the daily net assets of the Fund to finance activities intended to result in the sale of these shares. The Plan provides that the Fund may incur distribution expenses of up to 0.35% of average daily net assets, annually, to reimburse FSC. Subject to the terms described in the Expense Limitation note, FSC may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2015, FSC voluntarily waived its entire fee of $2,973,476. When FSC receives fees, it may pay some or all of them to financial intermediaries whose customers purchase shares.

Expense Limitation

Due to the possibility of changes in market conditions and other factors, there can be no assurance that the level of waivers/reimbursement/reduction of Fund expenses reflected in the financial highlights will be maintained in the future. However, the Adviser and certain of its affiliates (which may include FSC, FAS and FSSC) on their own initiative have agreed to waive certain amounts of their respective fees and/or reimburse expenses. Total annual fund operating expenses (as shown in the financial highlights, excluding extraordinary expenses and proxy-related expenses paid by the Fund, if any) paid by the Fund (after the voluntary waivers and/or reimbursements) will not exceed 1.05% (the “Fee Limit”), up to but not including the later of (the “Termination Date”): (a) August 1, 2016; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its applicable affiliates currently do not anticipate terminating or increasing these arrangements prior to the Termination Date, these arrangements may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Directors.

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Interfund Transactions

During the year ended May 31, 2015, the Fund engaged in purchase and sale transactions with funds that have a common investment adviser (or affiliated investment advisers), common Directors/Trustees, and/or common Officers. These purchase and sale transactions complied with Rule 17a-7 under the Act and amounted to $5,000,000 and $18,380,000, respectively.

General

Certain Officers and Directors of the Fund are Officers and Directors or Trustees of certain of the above companies. To efficiently facilitate payment, Directors'/Trustees' fees and certain expenses related to conducting meetings of the Directors/Trustees and other miscellaneous expenses are paid by an affiliate of the Adviser which in due course are reimbursed by the Fund. Such expenses may be included in Accrued and Miscellaneous Expenses on the Statement of Assets and Liabilities and Statement of Operations, respectively.

6. CONCENTRATION OF RISK

A substantial part of the Fund's portfolio may be comprised of obligations of banks. As a result, the Fund may be more susceptible to any economic, business, political or other developments which generally affect these entities.

7. LINE OF CREDIT

The Fund participates in a $100,000,000 unsecured, uncommitted revolving line of credit (LOC) agreement with PNC Bank. The LOC was made available for extraordinary or emergency purposes, primarily for financing redemption payments. Borrowings are charged interest at a rate offered to the Fund by PNC Bank at the time of the borrowing. As of May 31, 2015, there were no outstanding loans. During the year ended May 31, 2015, the Fund did not utilize the LOC.

8. INTERFUND LENDING

Pursuant to an Exemptive Order issued by the Securities and Exchange Commission (SEC), the Fund, along with other funds advised by subsidiaries of Federated Investors, Inc., may participate in an interfund lending program. This program provides an alternative credit facility allowing the Fund to borrow from other participating affiliated funds. As of May 31, 2015, there were no outstanding loans. During the year ended May 31, 2015, the program was not utilized.

9. REGULATORY MATTERS

On July 23, 2014, the SEC voted to amend the rules under the Act which currently govern the operations of the Fund. A significant change resulting from these amendments will be a requirement that institutional prime funds (i.e. not retail as defined in the amendments), transact fund shares based on a market-based Net Asset Value (NAV). Other types of money market funds may continue to transact fund shares at an NAV calculated using the amortized cost valuation method. Among additional disclosure and other requirements, the amendments also will permit a money market fund, or, in certain circumstances, require a money market fund (other than a government money market fund which satisfies the requirements of the amended rules) to impose liquidity fees on redemptions, and permit a money market fund to limit (or gate) redemptions for up to 10 business days in any 90-day period. The amendments have staggered compliance dates. Compliance with a majority of these amendments will be required on October 14, 2016, two years after the effective date for the rule amendments. The

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degree to which a money market fund will be impacted by the rule amendments will depend upon the type of fund and type of investors (retail or institutional). At this time, management is evaluating the implications of these amendments and their impact to the Fund's operations, financial statements and accompanying notes.

10. Subsequent EvenT

On June 3, 2015, the Fund filed a supplement to its current Prospectus notifying shareholders that the Directors have approved a proposed Agreement and Plan of Reorganization (Reorganization) pursuant to which Federated Prime Cash Obligations Fund would acquire all or substantially all of the assets of the Fund in complete liquidation and termination of the Fund. Information statements will be sent to shareholders explaining the Reorganization. The Reorganization is expected to occur in the fourth quarter of 2015.

Management has evaluated subsequent events through the date the financial statements were issued and determined that no additional events occurred that require disclosure.

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Report of Independent Registered Public Accounting Firm

TO THE BOARD OF directors OF Cash TRUST SERIES, INC. AND SHAREHOLDERS Of Federated PRIME cash Series:

We have audited the accompanying statement of assets and liabilities of Federated Prime Cash Series (the “Fund”) (one of the portfolios constituting Cash Trust Series, Inc.), including the portfolio of investments, as of May 31, 2015, and the related statement of operations for the year then ended, the statement of changes in net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended. These financial statements and financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

We conducted our audits in accordance with standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. We were not engaged to perform an audit of the Fund's internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements and financial highlights, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of May 31, 2015, by correspondence with the custodian and others. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Federated Prime Cash Series, a portfolio of Cash Trust Series, Inc., at May 31, 2015, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended, in conformity with U.S. generally accepted accounting principles.

Boston, Massachusetts
July 23, 2015

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Shareholder Expense Example (unaudited)

As a shareholder of the Fund, you incur ongoing costs, including management fees and to the extent applicable, distribution (12b-1) fees and/or other service fees and other Fund expenses. This Example is intended to help you to understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. It is based on an investment of $1,000 invested at the beginning of the period and held for the entire period from December 1, 2014 to May 31, 2015.

ACTUAL EXPENSES

The first section of the table below provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you incurred over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses attributable to your investment during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second section of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. Thus, you should not use the hypothetical account values and expenses to estimate the actual ending account balance or your expenses for the period. Rather, these figures are required to be provided to enable you to compare the ongoing costs of investing in the Fund with other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

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Please note that the expenses shown in the table are meant to highlight your ongoing costs only. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

	Beginning Account Value 12/1/2014	Ending Account Value 5/31/2015	Expenses Paid During Period1,2
Actual	$1,000	$1,000.10	$1.40
Hypothetical (assuming a 5% return before expenses)	$1,000	$1,023.54	$1.41

1

Expenses are equal to the Fund's annualized net expense ratio of 0.28%, multiplied by the average account value over the period, multiplied by 182/365 (to reflect the one-half-year period).

2

Actual and Hypothetical expenses paid during the period utilizing the Fund's current Fee Limit of 1.05% (as reflected in the Notes to Financial Statements, Note 5 under Expense Limitation), multiplied by the average account value over the period, multiplied by 182/365 (to reflect expenses paid as if they had been in effect throughout the most recent one-half-year period) would be $5.24 and $5.29, respectively.

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Board of Directors and Corporation Officers

The Board of Directors is responsible for managing the Corporation's business affairs and for exercising all the Corporation's powers except those reserved for the shareholders. The following tables give information about each Director and the senior officers of the Fund. Where required, the tables separately list Directors who are “interested persons” of the Fund (i.e., “Interested” Directors) and those who are not (i.e., “Independent” Directors). Unless otherwise noted, the address of each person listed is Federated Investors Tower, 1001 Liberty Avenue, Pittsburgh, PA 15222. The address of all Independent Directors listed is 4000 Ericsson Drive, Warrendale, PA 15086-7561; Attention: Mutual Fund Board. As of December 31, 2014, the Corporation comprised four portfolio(s), and the Federated Fund Family consisted of 40 investment companies (comprising 131 portfolios). Unless otherwise noted, each Officer is elected annually. Unless otherwise noted, each Director oversees all portfolios in the Federated Fund Family and serves for an indefinite term. The Fund's Statement of Additional Information includes additional information about Corporation Directors and is available, without charge and upon request, by calling 1-800-341-7400.

Interested DIRECTORS Background

Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years, Other Directorships Held and Previous Position(s)
John F. Donahue* Birth Date: July 28, 1924 Director Indefinite Term Began serving: May 1989	Principal Occupations: Director or Trustee of the Federated Fund Family; Chairman and Director, Federated Investors, Inc.; Chairman of the Federated Fund Family's Executive Committee. Previous Positions: Chairman of the Federated Fund Family; Trustee, Federated Investment Management Company; Chairman and Director, Federated Investment Counseling.

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Name Birth Date Positions Held with Corporation Date Service Began

Principal Occupation(s) for Past Five Years, Other Directorships Held and Previous Position(s)

J. Christopher Donahue* Birth Date: April 11, 1949 President and Director Indefinite Term Began serving: May 1989

Principal Occupations: Principal Executive Officer and President of certain of the Funds in the Federated Fund Family; Director or Trustee of the Funds in the Federated Fund Family; President, Chief Executive Officer and Director, Federated Investors, Inc.; Chairman and Trustee, Federated Investment Management Company; Trustee, Federated Investment Counseling; Chairman and Director, Federated Global Investment Management Corp.; Chairman, Federated Equity Management Company of Pennsylvania and Passport Research, Ltd. (investment advisory subsidiary of Federated); Trustee, Federated Shareholder Services Company; Director, Federated Services Company. Previous Positions: President, Federated Investment Counseling; President and Chief Executive Officer, Federated Investment Management Company, Federated Global Investment Management Corp. and Passport Research, Ltd.

* Family relationships and reasons for “interested” status: John F. Donahue is the father of J. Christopher Donahue; both are “interested” due to their beneficial ownership of shares of Federated Investors, Inc. and the positions they hold with Federated and its subsidiaries.

INDEPENDENT DIRECTORS Background

Name Birth Date Positions Held with Corporation Date Service Began

Principal Occupation(s) for Past Five Years, Other Directorships Held, Previous Position(s) and Qualifications

John T. Collins Birth Date: January 24, 1947 Director Indefinite Term Began serving: October 2013

Principal Occupations: Director or Trustee of the Federated Fund Family; Chairman and CEO, The Collins Group, Inc. (a private equity firm). Other Directorships Held: Director, Chair of the Compensation Committee, Audit Committee member, KLX Corp. Qualifications: Mr. Collins has served in several business and financial management roles and directorship positions throughout his career. Mr. Collins serves as Chairman Emeriti, Bentley University. Mr. Collins previously served as Director, FleetBoston Financial Corp.; Director and Audit Committee Member, Bank of America Corp. and Director, Beth Israel Deaconess Medical Center (Harvard University Affiliate Hospital).

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Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years, Other Directorships Held, Previous Position(s) and Qualifications
Maureen Lally-Green Birth Date: July 5, 1949 Director Indefinite Term Began serving: August 2009	Principal Occupations: Director or Trustee of the Federated Fund Family; Adjunct Professor of Law, Duquesne University School of Law. Other Directorships Held: Director, CONSOL Energy Inc. Qualifications: Judge Lally-Green has served in various legal and business roles and directorship positions throughout her career. Judge Lally-Green previously served as: Associate General Secretary, Diocese of Pittsburgh; Professor of Law, Duquesne University School of Law and was a member of the Superior Court of Pennsylvania. Judge Lally-Green also holds the positions of: Member, Pennsylvania State Board of Education; Director, Saint Vincent College; Director and Chair, UPMC Mercy Hospital; Regent, St. Vincent Seminary; Director, Epilepsy Foundation of Western and Central Pennsylvania; Director, Our Campaign for the Church Alive!, Inc.; Director, Pennsylvania Bar Institute; and Director, Catholic High Schools of the Diocese of Pittsburgh, Inc. Judge Lally-Green has held the positions of: Director, Auberle; Director, Ireland Institute of Pittsburgh; Director, Saint Thomas More Society; and Director Cardinal Wuerl Catholic High School.
Peter E. Madden Birth Date: March 16, 1942 Director Indefinite Term Began serving: August 1991	Principal Occupation: Director or Trustee, and Chair of the Board of Directors or Trustees, of the Federated Fund Family; Retired. Other Directorships Held: None. Qualifications: Mr. Madden has served in several business management, mutual fund services and directorship positions throughout his career. Mr. Madden previously served as President, Chief Operating Officer and Director, State Street Bank and Trust Company (custodian bank) and State Street Corporation (financial services). He was Director, VISA USA and VISA International and Chairman and Director, Massachusetts Bankers Association. Mr. Madden served as Director, Depository Trust Corporation and Director, The Boston Stock Exchange. Mr. Madden also served as a Representative to the Commonwealth of Massachusetts General Court.
Charles F. Mansfield, Jr. Birth Date: April 10, 1945 Director Indefinite Term Began serving: January 1999	Principal Occupations: Director or Trustee of the Federated Fund Family; Management Consultant. Other Directorships Held: None. Qualifications: Mr. Mansfield has served in several banking, business management and educational roles and directorship positions throughout his career. Mr. Mansfield previously served as Chief Executive Officer, PBTC International Bank; Partner, Arthur Young & Company (now Ernst & Young LLP); Chief Financial Officer of Retail Banking Sector, Chase Manhattan Bank; Senior Vice President, HSBC Bank USA (formerly, Marine Midland Bank); Vice President, Citibank; Assistant Professor of Banking and Finance, Frank G. Zarb School of Business, Hofstra University; Executive Vice President DVC Group, Inc. (marketing, communications and technology).

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Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years, Other Directorships Held, Previous Position(s) and Qualifications
Thomas M. O'Neill Birth Date: June 14, 1951 Director Indefinite Term Began serving: October 2006	Principal Occupations: Director or Trustee, Vice Chair of the Audit Committee of the Federated Fund Family; Sole Proprietor, Navigator Management Company (investment and strategic consulting). Other Directorships Held: None. Qualifications: Mr. O'Neill has served in several business, mutual fund and financial management roles and directorship positions throughout his career. Mr. O'Neill serves as Director, Medicines for Humanity and Director, The Golisano Children's Museum of Naples, Florida. Mr. O'Neill previously served as Chief Executive Officer and President, Managing Director and Chief Investment Officer, Fleet Investment Advisors; President and Chief Executive Officer, Aeltus Investment Management, Inc.; General Partner, Hellman, Jordan Management Co., Boston, MA; Chief Investment Officer, The Putnam Companies, Boston, MA; Credit Analyst and Lending Officer, Fleet Bank; Director and Consultant, EZE Castle Software (investment order management software); and Director, Midway Pacific (lumber).
P. Jerome Richey Birth Date: February 23, 1949 Director Indefinite Term Began serving: October 2013	Principal Occupations: Director or Trustee of the Federated Fund Family; Management Consultant. Other Directorships Held: None. Qualifications: Mr. Richey has served in several business and legal management roles and directorship positions throughout his career. Mr. Richey most recently held the positions of Senior Vice Chancellor and Chief Legal Officer, University of Pittsburgh. Mr. Richey serves as Board Member, Epilepsy Foundation of Western Pennsylvania and Board member, World Affairs Council of Pittsburgh. Mr. Richey previously served as Chief Legal Officer and Executive Vice President, CONSOL Energy Inc. and Shareholder, Buchanan Ingersoll & Rooney PC (a law firm).
John S. Walsh Birth Date: November 28, 1957 Director Indefinite Term Began serving: January 1999	Principal Occupations: Director or Trustee, Chair of the Audit Committee of the Federated Fund Family; President and Director, Heat Wagon, Inc. (manufacturer of construction temporary heaters); President and Director, Manufacturers Products, Inc. (distributor of portable construction heaters); President, Portable Heater Parts, a division of Manufacturers Products, Inc. Other Directorships Held: None. Qualifications: Mr. Walsh has served in several business management roles and directorship positions throughout his career. Mr. Walsh previously served as Vice President, Walsh & Kelly, Inc. (paving contractors).

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OFFICERS

Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years and Previous Position(s)
John W. McGonigle Birth Date: October 26, 1938 EXECUTIVE VICE PRESIDENT AND SECRETARY Officer since: May 1989	Principal Occupations: Executive Vice President and Secretary of the Federated Fund Family; Vice Chairman, Executive Vice President, Secretary and Director, Federated Investors, Inc. Previous Positions: Trustee, Federated Investment Management Company and Federated Investment Counseling; Director, Federated Global Investment Management Corp., Federated Services Company and Federated Securities Corp.
Lori A. Hensler Birth Date: January 6, 1967 TREASURER Officer since: April 2013	Principal Occupations: Principal Financial Officer and Treasurer of the Federated Fund Family; Senior Vice President, Federated Administrative Services; Financial and Operations Principal for Federated Securities Corp. and Edgewood Services, Inc.; and Assistant Treasurer, Federated Investors Trust Company. Ms. Hensler has received the Certified Public Accountant designation. Previous Positions: Controller of Federated Investors, Inc.; Senior Vice President and Assistant Treasurer, Federated Investors Management Company; Treasurer, Federated Investors Trust Company; Assistant Treasurer, Federated Administrative Services, Federated Administrative Services, Inc., Federated Securities Corp., Edgewood Services, Inc., Federated Advisory Services Company, Federated Equity Management Company of Pennsylvania, Federated Global Investment Management Corp., Federated Investment Counseling, Federated Investment Management Company, Passport Research, Ltd., and Federated MDTA, LLC; Financial and Operations Principal for Federated Securities Corp., Edgewood Services, Inc. and Southpointe Distribution Services, Inc.
Peter J. Germain Birth Date: September 3, 1959 CHIEF LEGAL OFFICER Officer since: January 2005	Principal Occupations: Mr. Germain is Chief Legal Officer of the Federated Fund Family. He is General Counsel and Vice President, Federated Investors, Inc.; President, Federated Administrative Services and Federated Administrative Services, Inc.; Vice President, Federated Securities Corp.; Secretary, Federated Private Asset Management, Inc.; and Secretary, Retirement Plan Service Company of America. Mr. Germain joined Federated in 1984 and is a member of the Pennsylvania Bar Association. Previous Positions: Deputy General Counsel, Special Counsel, Managing Director of Mutual Fund Services, Federated Investors, Inc.; Senior Vice President, Federated Services Company; and Senior Corporate Counsel, Federated Investors, Inc.
Richard B. Fisher Birth Date: May 17, 1923 Vice Chairman Officer since: August 2002	Principal Occupations: Vice Chairman or Vice President of some of the Funds in the Federated Fund Family; Vice Chairman, Federated Investors, Inc.; Chairman, Federated Securities Corp. Previous Positions: President and Director or Trustee of some of the Funds in the Federated Fund Family; Executive Vice President, Federated Investors, Inc.; Director and Chief Executive Officer, Federated Securities Corp.

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Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years and Previous Position(s)
Brian P. Bouda Birth Date: February 28, 1947 CHIEF COMPLIANCE OFFICER AND SENIOR VICE PRESIDENT Officer since: August 2004; Retiring July 29, 2015	Principal Occupations: Senior Vice President and Chief Compliance Officer of the Federated Fund Family; Vice President and Chief Compliance Officer of Federated Investors, Inc. and Chief Compliance Officer of certain of its subsidiaries. Mr. Bouda joined Federated in 1999 and is a member of the American Bar Association and the State Bar Association of Wisconsin. Previous Positions: Served in Senior Management positions with a large regional banking organization.
Stephen Van Meter Birth Date: June 5, 1975 CHIEF COMPLIANCE OFFICER AND SENIOR VICE PRESIDENT Officer since: Effective July 30, 2015	Principal Occupations: Senior Vice President and Chief Compliance Officer of the Federated Fund Family; Vice President and Chief Compliance Officer of Federated Investors, Inc. and Chief Compliance Officer of certain of its subsidiaries. Mr. Van Meter joined Federated in October 2011. He holds FINRA licenses under Series 3, 7, 24 and 66. Previous Positions: Mr. Van Meter previously held the position of Compliance Operating Officer, Federated Investors, Inc. Prior to joining Federated, Mr. Van Meter served at the United States Securities and Exchange Commission in the positions of Senior Counsel, Office of Chief Counsel, Division of Investment Management and Senior Counsel, Division of Enforcement.
Deborah A. Cunningham Birth Date: September 15, 1959 CHIEF INVESTMENT OFFICER Officer since: May 2004	Principal Occupations: Deborah A. Cunningham was named Chief Investment Officer of Federated's money market products in 2004. She joined Federated in 1981 and has been a Senior Portfolio Manager since 1997 and an Executive Vice President of the Fund's Adviser since 2009. Ms. Cunningham has received the Chartered Financial Analyst designation and holds an M.S.B.A. in Finance from Robert Morris College.
Paige M. Wilhelm Birth Date: May 28, 1962 Vice President Officer since: June 2012 Portfolio Manager since: April 1997	Principal Occupations: Paige M. Wilhelm has been the Fund's Portfolio Manager since April 1997. She is Vice President of the Corporation with respect to the Fund. Ms. Wilhelm joined Federated in 1985 and has been a Sr. Vice President of the Funds Adviser since January 2006 and a Senior Portfolio Manager since January 2004. She is responsible for portfolio management and research in the fixed-income area concentrating on taxable money market instruments. Previous associations include Senior Credit Analyst, Federated Investors; Performance Analysis Supervisor; Performance Analyst, Federated Investment Counseling. Ms. Wilhelm is a member of the CFA Society of Pittsburgh and received her B.S. from Indiana University and her M.B.A. from Duquesne University.

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Evaluation and Approval of Advisory Contract–May 2015

Federated Prime Cash Series (the “Fund”)

Following a review and recommendation of approval by the Fund's independent directors, the Fund's Board reviewed and approved at its May 2015 meetings the Fund's investment advisory contract for an additional one-year term. The Board's decision regarding the contract reflects the exercise of its business judgment on whether to continue the existing arrangements.

In this connection, the Federated Funds' Board had previously appointed a Senior Officer, whose duties include specified responsibilities relating to the process by which advisory fees are to be charged to a Federated fund. The Senior Officer has the authority to retain consultants, experts, or staff as may be reasonably necessary to assist in the performance of his duties, reports directly to the Board, and may be terminated only with the approval of a majority of the independent members of the Board. The Senior Officer prepared and furnished to the Board an independent, written evaluation that covered topics discussed below (the “Evaluation”). The Board considered that Evaluation, along with other information, in deciding to approve the advisory contract.

The Board is also familiar with and considered judicial decisions concerning allegedly excessive investment advisory fees, which have indicated that the following factors may be relevant to an Adviser's fiduciary duty with respect to its receipt of compensation from a fund: the nature and quality of the services provided by the Adviser to a fund and its shareholders, including the performance and expenses of the fund and of comparable funds; the Adviser's cost of providing the services, including the profitability to the Adviser of providing advisory services to a fund; the extent to which the Adviser may realize “economies of scale” as a fund grows larger and, if such economies of scale exist, whether they have been shared with a fund and its shareholders or the family of funds; any “fall-out financial benefits” that accrue to the Adviser because of its relationship with a fund (including research services received from brokers that execute fund trades and any fees paid to affiliates of the Adviser for services rendered to a fund); comparative fee structures, including a comparison of fees paid to the Adviser with those paid by similar funds; and the extent of care, conscientiousness and independence with which the Board members perform their duties and their expertise, including whether they are fully informed about all facts the Board deems relevant to its consideration of the Adviser's services and fees. The Board noted that SEC disclosure requirements regarding the basis for the Board's approval of the Fund's advisory contract generally track the factors listed above. Consistent with these judicial decisions and SEC disclosure requirements, the Board also considered management fees

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charged to institutional and other clients of the Adviser for what might be viewed as like services. The Board was aware of these factors and was guided by them in its review of the Fund's advisory contract to the extent it considered them to be appropriate and relevant, as discussed further below.

The Board considered and weighed these circumstances in light of its substantial accumulated experience in governing the Fund and working with Federated on matters relating to the Federated funds, and was assisted in its deliberations by independent legal counsel. Throughout the year, and in connection with its May meetings, the Board requested and received substantial and detailed information about the Fund and the Federated organization that was in addition to the extensive materials that comprise and accompany the Senior Officer's Evaluation. Federated provided much of this information at each regular meeting of the Board, and furnished additional substantial information in connection with the May meeting at which the Board's formal review of the advisory contract occurred. At this May meeting, senior management of the Adviser also met with the independent directors and their counsel to discuss the materials presented and any other matters thought relevant by the Adviser or the directors. Between regularly scheduled meetings, the Board also received information on particular matters as the need arose. Thus, the Board's consideration of the advisory contract included review of the Senior Officer's Evaluation, accompanying data and additional information covering such matters as: the Adviser's investment philosophy, revenue, profitability, personnel and processes; investment and operating strategies; the Fund's short- and long-term performance (in absolute terms, both on a gross basis and net of expenses, as well as in relationship to its particular investment program and certain competitor or “peer group” funds and/or other benchmarks, as appropriate), and comments on the reasons for performance; the Fund's investment objectives; the Fund's expenses (including the advisory fee itself and the overall expense structure of the Fund, both in absolute terms and relative to similar and/or competing funds, with due regard for contractual or voluntary expense limitations); the use and allocation of brokerage commissions derived from trading the Fund's portfolio securities (if any); and the nature, quality and extent of the advisory and other services provided to the Fund by the Adviser and its affiliates. The Board also considered the preferences and expectations of Fund shareholders; the entrepreneurial risk assumed by the Adviser in sponsoring the funds; the continuing state of competition in the mutual fund industry and market practices; the range of comparable fees for similar funds in the mutual fund industry; the Fund's relationship to the Federated family of funds which include a comprehensive array of funds with different investment objectives, policies and strategies which are available for exchange without the incurrence of additional sales charges; compliance and audit reports concerning the Federated funds and the Federated companies that service them (including communications from regulatory agencies), as well as Federated's responses to any issues raised therein; and relevant developments in

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the mutual fund industry and how the Federated funds and/or Federated are responding to them. The Board's evaluation process is evolutionary. The criteria considered and the emphasis placed on relevant criteria change in recognition of changing circumstances in the mutual fund marketplace.

While mindful that courts have cautioned against giving such comparisons too much weight, the Board has found the use of comparisons of the Fund's fees and expenses to other mutual funds with comparable investment programs to be relevant. In this regard, the Board was presented with, and considered, information regarding the contractual advisory fee rates, net advisory fee rates and total expense ratios relative to a fund's peers. The Board focused on comparisons with other similar mutual funds more heavily than non-mutual fund products or services because it is believed that they are more relevant. For example, other mutual funds are the products most like the Fund, they are readily available to Fund shareholders as alternative investment vehicles, and they are the type of investment vehicle in fact chosen and maintained by the Fund's investors. The range of their fees and expenses therefore appears to be a relevant indicator of what consumers have found to be reasonable in the precise marketplace in which the Fund competes.

The Board reviewed the contractual advisory fee rate, net advisory fee rate where partially waived and other expenses of the Fund and noted the position of the Fund's fee rates relative to its peers. In this regard, the Board noted that the contractual advisory fee rate was above the median of the relevant peer group, but the Board noted the applicable waivers and reimbursements and that the overall expense structure of the Fund remained competitive. The Board will continue to monitor advisory fees and other expenses borne by the Fund in the context of the other factors considered relevant by the Board.

By contrast, the Senior Officer has reviewed Federated's fees for providing advisory services to products outside the Federated family of funds (e.g., institutional and separate accounts and sub-adviser services). He concluded that mutual funds and institutional accounts are inherently different products. Those differences include, but are not limited to, different types of targeted investors; being subject to different laws and regulations; different legal structures; different average account sizes and portfolio management techniques made necessary by different cash flows and different associated costs; and the time spent by portfolio managers and their teams, funds financial services, legal, compliance and risk management in reviewing securities pricing, addressing different administrative responsibilities, addressing different degrees of risk associated with management and a variety of different costs. The Senior Officer did not consider these fee schedules to be determinative in judging the appropriateness of mutual fund advisory fees.

Annual Shareholder Report

32

The Fund's ability to deliver competitive performance when compared to its peer group was also deemed to be relevant by the Board as a useful indicator of how the Adviser is executing the Fund's investment program, which in turn was one of the Board's considerations in reaching a conclusion that the nature, extent, and quality of the Adviser's investment management services were such as to warrant continuation of the advisory contract.

The Senior Officer reviewed information compiled by Federated, using data supplied by independent fund ranking organizations, regarding the performance of, and fees charged by, other mutual funds, noting his view that comparisons to fund peer groups may be helpful, though not conclusive, in judging the reasonableness of the proposed fees. The Board considered, in evaluating such comparisons, that in some cases individual funds may exhibit significant and unique differences in their objectives and management techniques when compared to other funds within an industry peer group.

The Fund's performance was above the median of the relevant peer group for the one-year period covered by the Evaluation.

The Board also received financial information about Federated, including information regarding the compensation and benefits Federated derived from its relationships with the Federated funds. This information covered not only the fees under the advisory contracts, but also fees received by Federated's subsidiaries for providing other services to the Federated funds under separate contracts (e.g., for serving as the Federated funds' administrator). The information also detailed any indirect benefit Federated may derive from its receipt of research services from brokers who execute Federated fund trades. In addition, the Board considered the fact that, in order for a fund to be competitive in the marketplace, Federated and its affiliates frequently waived fees and/or reimbursed expenses and have disclosed to fund investors and/or indicated to the Board their intention to do so in the future, where appropriate. Moreover, the Board receives regular reporting as to the institution, adjustment or elimination of these voluntary waivers.

In addition, over the past two years, following discussions regarding the Senior Officer's recommendations, Federated made meaningful reductions to the contractual advisory fees for several Funds. In May 2014, the Senior Officer recommended that Federated review the fee structures of its money market funds to determine whether it would be appropriate to consider alternative pricing structures. Federated has combined that review with its consideration of the re-structuring of its money market fund product line in response to the recently adopted amendments to Rule 2a-7 under the Investment Company Act of 1940, as amended (the “1940 Act”).

At the Board meeting in May 2015, following previous recommendations of the Senior Officer, Federated proposed, and the Board approved, reductions in the contractual advisory fees of certain other Funds.

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33

Federated furnished information, requested by the Senior Officer, that reported revenues on a fund-by-fund basis and made estimates of the allocation of expenses on a fund-by-fund basis, using allocation methodologies specified by the Senior Officer. The Senior Officer noted that, while these cost allocation reports apply consistent allocation processes, the inherent difficulties in allocating costs continues to cause the Senior Officer to question the precision of the process and to conclude that such reports may be unreliable, since a single change in an allocation estimate may dramatically alter the resulting estimate of cost and/or profitability of a fund and may produce unintended consequences. The allocation information, including the Senior Officer's view that fund-by-fund estimations may be unreliable, was considered in the analysis by the Board.

The Board and the Senior Officer also reviewed information compiled by Federated comparing profitability information for Federated to other publicly held fund management companies. In this regard, the Senior Officer concluded that Federated's profit margins did not appear to be excessive. The Senior Officer also noted that Federated appeared financially sound, with the resources to fulfill its obligations under its contracts with the Funds.

The Senior Officer's Evaluation also discussed the notion of possible realization of “economies of scale” as a fund grows larger. The Board considered in this regard that the Adviser has made significant and long-term investments in areas that support all of the Federated family of funds, such as personnel and processes for the portfolio management, shareholder services, compliance, internal audit, and risk management functions; and systems technology; and that the benefits of these efforts (as well as any economies of scale, should they exist) were likely to be enjoyed by the fund family as a whole. Federated, as it does throughout the year, and again in connection with the Board's review, furnished information relative to revenue sharing or adviser paid fees. Federated and the Senior Officer noted that this information should be viewed to determine if there was an incentive to either not apply breakpoints or to apply breakpoints at higher levels and should not be viewed to determining the appropriateness of advisory fees, because it would represent marketing and distribution expenses. Finally, the Board also noted the absence of any applicable regulatory or industry guidelines on this subject, which (as discussed in the Senior Officer's Evaluation) is compounded by the lack of any common industry practice or general pattern with respect to structuring fund advisory fees with “breakpoints” that serve to reduce the fee as the fund attains a certain size.

The Senior Officer noted that, subject to the comments and recommendations made within his Evaluation, his observations and the information accompanying the Evaluation supported a finding by the Board that the management fees for each of the funds were reasonable. Under these circumstances, no objection was raised to the continuation of, the Fund's advisory contract.

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In its decision to continue an existing investment advisory contract, the Board was mindful of the potential disruptions of the Fund's operations and various risks, uncertainties and other effects that could occur as a result of a decision to terminate or not renew an advisory contract. In particular, the Board recognized that many shareholders have invested in the Fund on the strength of the Adviser's industry standing and reputation and with the expectation that the Adviser will have a continuing role in providing advisory services to the Fund. Thus, the Board's approval of the advisory contract reflected the fact that it is the shareholders who have effectively selected the Adviser by virtue of having invested in the Fund. The Board concluded that, in light of the factors discussed above, including the nature, quality and scope of the services provided to the Fund by the Adviser and its affiliates, continuation of the advisory contract was appropriate.

The Board based its decision to approve the advisory contract on the totality of the circumstances and relevant factors and with a view to past and future long-term considerations. Not all of the factors and considerations identified above were necessarily relevant to the Fund, nor did the Board consider any one of them to be determinative. With respect to the factors that were relevant, the Board's decision to approve the contract reflects its determination that Federated's performance and actions provided a satisfactory basis to support the decision to continue the existing arrangements.

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Voting Proxies on Fund Portfolio Securities

A description of the policies and procedures that the Fund uses to determine how to vote proxies, if any, relating to securities held in the Fund's portfolio is available, without charge and upon request, by calling 1-800-341-7400. A report on “Form N-PX” of how the Fund voted any such proxies during the most recent 12-month period ended June 30 is available via the Proxy Voting Record (Form N-PX) link associated with the Fund and share class name at www.FederatedInvestors.com/FundInformation. Form N-PX filings are also available at the SEC's website at www.sec.gov.

Quarterly Portfolio Schedule

The Fund files with the SEC a complete schedule of its portfolio holdings, as of the close of the first and third quarters of its fiscal year, on “Form N-Q.” These filings are available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, DC. (Call 1-800-SEC-0330 for information on the operation of the Public Reference Room.) You may also access this information via the link to the Fund and share class name at www.FederatedInvestors.com/FundInformation.

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Mutual funds are not bank deposits or obligations, are not guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency. Investment in mutual funds involves investment risk, including the possible loss of principal. Although money market funds seek to maintain a stable net asset value of $1.00 per share, there is no assurance that they will be able to do so.

This Report is authorized for distribution to prospective investors only when preceded or accompanied by the Fund's Prospectus, which contains facts concerning its objective and policies, management fees, expenses and other information.

Federated Prime Cash Series
Federated Investors Funds
4000 Ericsson Drive
Warrendale, PA 15086-7561

Contact us at FederatedInvestors.com
or call 1-800-341-7400.

Federated Securities Corp., Distributor

CUSIP 147551105

28566 (7/15)

Federated is a registered trademark of Federated Investors, Inc.
2015 ©Federated Investors, Inc.

Annual Shareholder Report

May 31, 2015

Ticker CTTXX

Federated Treasury Cash Series

A Portfolio of Cash Trust Series, Inc.

Not FDIC Insured
May Lose Value

No Bank Guarantee

CONTENTS

Portfolio of Investments Summary Tables	1
Portfolio of Investments	2
Financial Highlights	6
Statement of Assets and Liabilities	7
Statement of Operations	8
Statement of Changes in Net Assets	9
Notes to Financial Statements	10
Report of Independent Registered Public Accounting Firm	16
Shareholder Expense Example	17
Board of Directors and Corporation Officers	18
Evaluation and Approval of Advisory Contract	24
Voting Proxies on Fund Portfolio Securities	30
Quarterly Portfolio Schedule	30

Portfolio of Investments Summary Tables (unaudited)

At May 31, 2015, the Fund's portfolio composition¹ was as follows:

Portfolio Composition	Percentage of Total Net Assets
Repurchase Agreements	69.2%
U.S. Treasury Securities	24.3%
Other Assets and Liabilities—Net2	6.5%
TOTAL	100.0%

At May 31, 2015, the Fund's effective maturity³ schedule was as follows:

Securities With an Effective Maturity of:	Percentage of Total Net Assets
1-7 Days	72.0%
8-30 Days	1.3%
31-90 Days	8.6%
91-180 Days	8.2%
181 Days or more	3.4%
Other Assets and Liabilities—Net2	6.5%
TOTAL	100.0%

1	See the Fund's Prospectus and Statement of Additional Information for a description of the principal types of securities in which the Fund invests.
2	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.
3	Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940, which regulates money market mutual funds.

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1

Portfolio of Investments

May 31, 2015

Principal Amount			Value
		U.S. TREASURY—24.3%
$32,000,000	1	United States Treasury Bills, 0.145%, 9/17/2015	$31,986,080
20,000,000	1	United States Treasury Bills, 0.155%, 6/25/2015	19,997,933
45,000,000	2	United States Treasury Floating Rate Notes, 0.060% - 0.084%, 6/2/2015	44,998,559
87,500,000		United States Treasury Notes, 0.250% - 1.750%, 7/31/2015	87,713,014
17,000,000		United States Treasury Notes, 0.250%, 7/15/2015	17,001,843
8,500,000		United States Treasury Notes, 0.250%, 8/15/2015	8,502,427
21,000,000		United States Treasury Notes, 0.250%, 9/15/2015	21,006,971
9,000,000		United States Treasury Notes, 0.250%, 10/15/2015	9,003,663
5,000,000		United States Treasury Notes, 0.250%, 4/15/2016	4,994,451
25,000,000		United States Treasury Notes, 0.375%, 6/30/2015	25,004,972
6,000,000		United States Treasury Notes, 0.375%, 11/15/2015	6,005,922
14,000,000		United States Treasury Notes, 0.375%, 3/15/2016	14,009,981
23,500,000		United States Treasury Notes, 1.250%, 8/31/2015	23,566,067
38,500,000		United States Treasury Notes, 1.250%, 9/30/2015	38,642,117
10,000,000		United States Treasury Notes, 1.375%, 11/30/2015	10,058,036
25,250,000		United States Treasury Notes, 2.125%, 12/31/2015	25,526,870
		TOTAL U.S. TREASURY	388,018,906
		REPURCHASE AGREEMENTS—69.2%
90,000,000		Interest in $100,000,000 joint repurchase agreement 0.10%, dated 5/29/2015 under which ABN Amro Bank N.V., Netherlands will repurchase securities provided as collateral for $100,000,833 on 6/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 8/15/2041 and the market value of those underlying securities was $102,000,880.	90,000,000
90,000,000		Interest in $100,000,000 joint repurchase agreement 0.09%, dated 5/29/2015 under which BMO Capital Markets Corp. will repurchase securities provided as collateral for $100,000,750 on 6/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 11/15/2044 and the market value of those underlying securities was $102,000,766.	90,000,000
30,000,000	3	Interest in $500,000,000 joint repurchase agreement 0.09%, dated 5/15/2015 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $500,075,000 on 7/14/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 8/15/2044 and the market value of those underlying securities was $510,021,743.	30,000,000

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2

Principal Amount			Value
		REPURCHASE AGREEMENTS—continued
$30,000,000	3	Interest in $500,000,000 joint repurchase agreement 0.09%, dated 5/20/2015 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $500,125,000 on 8/28/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2045 and the market value of those underlying securities was $510,015,343.	$30,000,000
31,000,000	3	Interest in $500,000,000 joint repurchase agreement 0.10%, dated 4/10/2015 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $500,083,333 on 6/9/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2042 and the market value of those underlying securities was $510,073,683.	31,000,000
15,000,000	3	Interest in $250,000,000 joint repurchase agreement 0.07%, dated 5/26/2015 under which Bank of Montreal will repurchase securities provided as collateral for $250,014,583 on 6/25/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 8/15/2040 and the market value of those underlying securities was $255,003,053.	15,000,000
160,000,000		Interest in $200,000,000 joint repurchase agreement 0.10%, dated 5/29/2015 under which Bank of Nova Scotia will repurchase securities provided as collateral for $200,001,667 on 6/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 5/15/2044 and the market value of those underlying securities was $204,001,702.	160,000,000
45,000,000	3	Interest in $700,000,000 joint repurchase agreement 0.07%, dated 5/19/2015 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $700,040,833 on 6/18/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2023 and the market value of those underlying securities was $714,018,145.	45,000,000
25,000,000	3	Interest in $500,000,000 joint repurchase agreement 0.07%, dated 5/22/2015 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $500,030,139 on 6/22/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 5/15/2040 and the market value of those underlying securities was $510,009,982.	25,000,000
35,000,000	3	Interest in $1,000,000,000 joint repurchase agreement 0.08%, dated 5/11/2015 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $1,000,066,667 on 6/10/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 8/15/2044 and the market value of those underlying securities was $1,020,047,621.	35,000,000

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Principal Amount			Value
		REPURCHASE AGREEMENTS—continued
$25,000,000	3	Interest in $400,000,000 joint repurchase agreement 0.08%, dated 5/18/2015 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $400,026,667 on 6/17/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2041 and the market value of those underlying securities was $408,012,730.	$25,000,000
90,000,000		Interest in $100,000,000 joint repurchase agreement 0.09%, dated 5/29/2015 under which CIBC World Markets Corp. will repurchase securities provided as collateral for $100,000,750 on 6/1/2015. The securities provided as collateral at the end of the period held with JPMorgan Chase tri-party agent, were U.S. Treasury securities with various maturities to 5/15/2045 and the market value of those underlying securities was $102,001,336.	90,000,000
38,411,000		Interest in $3,500,000,000 joint repurchase agreement 0.09%, dated 5/29/2015 under which Credit Agricole CIB New York will repurchase securities provided as collateral for $3,500,026,250 on 6/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 5/15/2045 and the market value of those underlying securities was $3,570,026,786.	38,411,000
60,000,000	3	Interest in $500,000,000 joint repurchase agreement 0.08%, dated 5/13/2015 under which J.P. Morgan Securities LLC will repurchase securities provided as collateral for $500,033,333 on 6/12/2015. The securities provided as collateral at the end of the period held with JPMorgan Chase tri-party agent, were U.S. Treasury securities with various maturities to 5/15/2024 and the market value of those underlying securities was $510,018,923.	60,000,000
300,000,000		Interest in $750,000,000 joint repurchase agreement 0.08%, dated 5/29/2015 under which Mitsubishi UFJ Securities (USA), Inc. will repurchase securities provided as collateral for $750,005,000 on 6/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 1/15/2027 and the market value of those underlying securities was $765,005,104.	300,000,000
40,000,000	3	Interest in $850,000,000 joint repurchase agreement 0.08%, dated 5/6/2015 under which Societe Generale, New York will repurchase securities provided as collateral for $850,062,333 on 6/8/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2044 and the market value of those underlying securities was $867,050,150.	40,000,000
		TOTAL REPURCHASE AGREEMENTS (AT COST)	1,104,411,000
		TOTAL INVESTMENTS—93.5% (AT AMORTIZED COST)4	1,492,429,906
		OTHER ASSETS AND LIABILITIES - NET—6.5%5	104,276,773
		TOTAL NET ASSETS—100%	$1,596,706,679

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4

1	Discount rate(s) at time of purchase.
2	Floating rate notes with current rate(s) and next reset date(s) shown.
3	Although the repurchase date is more than seven days after the date of purchase, the Fund has the right to terminate the repurchase agreement at any time with seven-days' notice.
4	Also represents cost for federal tax purposes.
5	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.

Note: The categories of investments are shown as a percentage of total net assets at May 31, 2015.

Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below:

Level 1—quoted prices in active markets for identical securities.

Level 2—other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.). Also includes securities valued at amortized cost.

Level 3—significant unobservable inputs (including the Fund's own assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities.

As of May 31, 2015, all investments of the Fund are valued at amortized cost, which is considered a Level 2 input, in valuing the Fund's assets.

See Notes which are an integral part of the Financial Statements

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5

Financial Highlights

(For a Share Outstanding Throughout Each Period)

Year Ended May 31	2015	2014	2013	2012	2011
Net Asset Value, Beginning of Period	$1.00	$1.00	$1.00	$1.00	$1.00
Income From Investment Operations:
Net investment income	—	—	—	—	—
Net realized gain on investments	0.00001	0.00001	—	0.00001	0.00001
TOTAL FROM INVESTMENT OPERATIONS	0.00001	0.00001	—	0.00001	0.00001
Less Distributions:
Distributions from net realized gain on investments	(0.0000)1	(0.0000)1	(0.0000)1	(0.0000)1	(0.0000)1
Net Asset Value, End of Period	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return2	0.00%3	0.00%3	0.00%3	0.00%3	0.00%3
Ratios to Average Net Assets:
Net expenses	0.08%	0.07%	0.16%	0.10%	0.19%
Net investment income	0.00%	0.00%	0.00%	0.00%	0.00%
Expense waiver/reimbursement4	1.00%	1.01%	0.92%	0.98%	0.89%
Supplemental Data:
Net assets, end of period (000 omitted)	$1,596,707	$2,358,885	$2,549,875	$2,355,609	$1,445,337

1	Represents less than $0.0001.
2	Based on net asset value.
3	Represents less than 0.01%.
4	This expense decrease is reflected in both the net expense and the net investment income ratios shown above.

See Notes which are an integral part of the Financial Statements

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6

Statement of Assets and Liabilities

May 31, 2015

Assets:
Investment in repurchase agreements	$1,104,411,000
Investment in securities	388,018,906
Total investment in securities, at amortized cost and fair value		$1,492,429,906
Cash		1,027
Income receivable		1,548,223
Receivable for investments sold		103,000,000
Receivable for shares sold		100
TOTAL ASSETS		1,596,979,256
Liabilities:
Payable to adviser (Note 5)	137,273
Payable for transfer agent fee	60,354
Payable for Directors'/Trustees' fees (Note 5)	1,864
Payable for portfolio accounting fees	28,163
Payable for share registration costs	35,397
Accrued expenses (Note 5)	9,526
TOTAL LIABILITIES		272,577
Net assets for 1,596,694,656 shares outstanding		$1,596,706,679
Net Assets Consist of:
Paid-in capital		$1,596,694,670
Accumulated net realized gain on investments		12,009
TOTAL NET ASSETS		$1,596,706,679
Net Asset Value, Offering Price and Redemption Proceeds Per Share:
$1,596,706,679 ÷ 1,596,694,656 shares outstanding, $0.001 par value, 12,500,000,000 shares authorized		$1.00

See Notes which are an integral part of the Financial Statements

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Statement of Operations

Year Ended May 31, 2015

Investment Income:
Interest			$1,561,314
Expenses:
Investment adviser fee (Note 5)		$10,073,030
Administrative fee (Note 5)		1,576,275
Custodian fees		68,611
Transfer agent fee		2,162,958
Directors'/Trustees' fees (Note 5)		16,295
Auditing fees		19,600
Legal fees		11,351
Portfolio accounting fees		167,034
Distribution services fee (Note 5)		2,014,606
Other service fees (Note 2)		5,036,515
Share registration costs		263,092
Printing and postage		126,292
Taxes		156,900
Miscellaneous (Note 5)		49,054
TOTAL EXPENSES		21,741,613
Waivers and Reimbursement:
Waiver of investment adviser fee (Note 5)	$(10,073,030)
Waivers/reimbursement of other operating expenses (Notes 2 and 5)	(10,107,269)
TOTAL WAIVERS AND REIMBURSEMENT		(20,180,299)
Net expenses			1,561,314
Net investment income			—
Net realized gain on investments			12,040
Change in net assets resulting from operations			$12,040

See Notes which are an integral part of the Financial Statements

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Statement of Changes in Net Assets

Year Ended May 31	2015	2014
Increase (Decrease) in Net Assets
Operations:
Net investment income	$—	$—
Net realized gain on investments	12,040	10,423
CHANGE IN NET ASSETS RESULTING FROM OPERATIONS	12,040	10,423
Distributions to Shareholders:
Distributions from net realized gain on investments	(8,149)	(2,305)
Share Transactions:
Proceeds from sale of shares	3,100,554,250	3,624,431,619
Net asset value of shares issued to shareholders in payment of distributions declared	8,004	2,294
Cost of shares redeemed	(3,862,744,332)	(3,815,432,507)
CHANGE IN NET ASSETS RESULTING FROM SHARE TRANSACTIONS	(762,182,078)	(190,998,594)
Change in net assets	(762,178,187)	(190,990,476)
Net Assets:
Beginning of period	2,358,884,866	2,549,875,342
End of period	$1,596,706,679	$2,358,884,866

See Notes which are an integral part of the Financial Statements

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Notes to Financial Statements

May 31, 2015

1. ORGANIZATION

Cash Trust Series, Inc. (the “Corporation”) is registered under the Investment Company Act of 1940, as amended (the “Act”), as an open-end management investment company. The Corporation consists of four portfolios. The financial statements included herein are only those of Federated Treasury Cash Series (the “Fund”), a diversified portfolio. The financial statements of the other portfolios are presented separately. The assets of each portfolio are segregated and a shareholder's interest is limited to the portfolio in which shares are held. Each portfolio pays its own expenses. The investment objective of the Fund is current income consistent with stability of principal and liquidity.

2. SIGNIFICANT ACCOUNTING POLICIES

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. These policies are in conformity with U.S. generally accepted accounting principles (GAAP).

Investment Valuation

Securities are valued at amortized cost. Under the amortized cost valuation method, an investment is valued initially at its cost as determined in accordance with GAAP. The Fund then adjusts the amount of interest income accrued each day over the term of the investment to account for any difference between the initial cost of the investment and the amount payable at its maturity. If amortized cost is determined not to approximate fair value, the value of the portfolio securities will be determined in accordance with the procedures described below.

The Directors have ultimate responsibility for determining the fair value of investments. The Directors have appointed a Valuation Committee (“Valuation Committee”) comprised of officers of the Fund, Federated Investment Management Company (“Adviser”) and certain of the Adviser's affiliated companies to assist in determining fair value of securities and in overseeing the comparison of amortized cost to market-based value. The Directors have also authorized the use of pricing services recommended by the Valuation Committee to provide fair value evaluations of the current value of certain investments for purposes of monitoring the relationship of market-based value and amortized cost. The Valuation Committee employs various methods for reviewing third-party pricing-service evaluations including periodic reviews of third-party pricing services' policies, procedures and valuation methods (including key inputs and assumptions), and review of price challenges by the Adviser based on recent market activity. In the event that market quotations and price evaluations are not available for an investment, the Valuation Committee determines the fair value of the investment in accordance with procedures adopted by the Directors. The Directors periodically review and approve the fair valuations made by the Valuation Committee and any changes made to the procedures.

Repurchase Agreements

The Fund may invest in repurchase agreements for short-term liquidity purposes. It is the policy of the Fund to require the other party to a repurchase agreement to transfer to the Fund's custodian or sub-custodian eligible securities or cash with a market value (after transaction costs) at least equal to the repurchase price to be paid under the repurchase

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agreement. The eligible securities are transferred to accounts with the custodian or sub-custodian in which the Fund holds a “securities entitlement” and exercises “control” as those terms are defined in the Uniform Commercial Code. The Fund has established procedures for monitoring the market value of the transferred securities and requiring the transfer of additional eligible securities if necessary to equal at least the repurchase price. These procedures also allow the other party to require securities to be transferred from the account to the extent that their market value exceeds the repurchase price or in exchange for other eligible securities of equivalent market value.

The insolvency of the other party or other failure to repurchase the securities may delay the disposition of the underlying securities or cause the Fund to receive less than the full repurchase price. Under the terms of the repurchase agreement, any amounts received by the Fund in excess of the repurchase price and related transaction costs must be remitted to the other party.

The Fund may enter into repurchase agreements in which eligible securities are transferred into joint trading accounts maintained by the custodian or sub-custodian for investment companies and other clients advised by the Fund's Adviser and its affiliates. The Fund will participate on a pro rata basis with the other investment companies and clients in its share of the securities transferred under such repurchase agreements and in its share of proceeds from any repurchase or other disposition of such securities.

Repurchase agreements are subject to Master Netting Agreements which are agreements between the Fund and its counterparties that provide for the net settlement of all transactions and collateral with the Fund, through a single payment, in the event of default or termination. Amounts presented on the Portfolio of Investments and Statement of Assets and Liabilities are not net settlement amounts but gross. As indicated above, the cash or securities to be repurchased, as shown on the Portfolio of Investments, exceeds the repurchase price to be paid under the agreement reducing the net settlement amount to zero.

Investment Income, Gains and Losses, Expenses and Distributions

Investment transactions are accounted for on a trade-date basis. Realized gains and losses from investment transactions are recorded on an identified-cost basis. Interest income and expenses are accrued daily. Distributions to shareholders are recorded on the ex-dividend date. Distributions of net investment income, if any, are declared daily and paid monthly. For the year ended May 31, 2015, unaffiliated third-party financial intermediaries waived $1,967,901 of transfer agent fees.

Other Service Fees

The Fund may pay other service fees up to 0.25% of the average daily net assets of the Fund to unaffiliated financial intermediaries or to Federated Shareholder Services Company (FSSC) for providing services to shareholders and maintaining shareholder accounts. Subject to the terms described in the Expense Limitation note, FSSC may voluntarily reimburse the Fund for other service fees. In addition, unaffiliated third-party financial intermediaries may waive other service fees. This waiver can be modified or terminated at any time. For the year ended May 31, 2015, unaffiliated third parties waived $5,036,515 of other services fees.

Premium and Discount Amortization

All premiums and discounts are amortized/accreted using the effective-interest-rate method.

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Federal Taxes

It is the Fund's policy to comply with the Subchapter M provision of the Internal Revenue Code and to distribute to shareholders each year substantially all of its income. Accordingly, no provision for federal income tax is necessary. As of and during the year ended May 31, 2015, the Fund did not have a liability for any uncertain tax positions. The Fund recognizes interest and penalties, if any, related to tax liabilities as income tax expense in the Statement of Operations. As of May 31, 2015, tax years 2012 through 2015 remain subject to examination by the Fund's major tax jurisdictions, which include the United States of America and the state of Maryland and the Commonwealth of Pennsylvania.

Other Taxes

As an open-end management investment company incorporated in the state of Maryland but domiciled in the Commonwealth of Pennsylvania, the Fund is subject to the Pennsylvania Franchise Tax. This franchise tax is assessed annually on the value of the Fund, as represented by average net assets for the tax year.

When-Issued and Delayed-Delivery Transactions

The Fund may engage in when-issued or delayed-delivery transactions. The Fund records when-issued securities on the trade date and maintains security positions such that sufficient liquid assets will be available to make payment for the securities purchased. Securities purchased on a when-issued or delayed-delivery basis are marked to market daily and begin earning interest on the settlement date. Losses may occur on these transactions due to changes in market conditions or the failure of counterparties to perform under the contract.

Other

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, expenses and revenues reported in the financial statements. Actual results could differ from those estimated. The Fund applies Investment Company accounting and reporting guidance.

3. CAPITAL STOCK

The following table summarizes capital stock activity:

Year Ended May 31	2015	2014
Shares sold	3,100,554,250	3,624,431,619
Shares issued to shareholders in payment of distributions declared	8,004	2,294
Shares redeemed	(3,862,744,332)	(3,815,432,507)
NET CHANGE RESULTING FROM FUND SHARE TRANSACTIONS	(762,182,078)	(190,998,594)

4. FEDERAL TAX INFORMATION

The tax character of distributions as reported on the Statement of Changes in Net Assets for the years ended May 31, 2015 and 2014, was as follows:

	2015	2014
Ordinary income1	$8,149	$2,305

1 For tax purposes, short-term capital gain distributions are considered ordinary income distributions.

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As of May 31, 2015, the components of distributable earnings on a tax-basis were as follows:

Undistributed ordinary income² $12,009

2 For tax purposes, short-term capital gains are considered ordinary income in determining distributable earnings.

5. INVESTMENT ADVISER FEE AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Adviser Fee

The advisory agreement between the Fund and the Adviser provides for an annual fee equal to 0.50% of the Fund's average daily net assets. Subject to the terms described in the Expense Limitation note, the Adviser may voluntarily choose to waive any portion of its fee and/or reimburse certain operating expenses of the Fund. For the year ended May 31, 2015, the Adviser voluntarily waived its entire fee of $10,073,030 and voluntarily reimbursed $1,088,247 of other operating expenses.

Administrative Fee

Federated Administrative Services (FAS), under the Administrative Services Agreement, provides the Fund with administrative personnel and services. For purposes of determining the appropriate rate breakpoint, “Investment Complex” is defined as all of the Federated Funds subject to a fee under the Administrative Services Agreement. The fee paid to FAS is based on the average daily net assets of the Investment Complex as specified below, plus certain out-of-pocket expenses:

Administrative Fee	Average Daily Net Assets of the Investment Complex
0.150%	on the first $5 billion
0.125%	on the next $5 billion
0.100%	on the next $10 billion
0.075%	on assets in excess of $20 billion

Subject to the terms described in the Expense Limitation note, FAS may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2015, the annualized fee paid to FAS was 0.078% of average daily net assets of the Fund.

Distribution Services Fee

The Fund has adopted a Distribution Plan (the “Plan”) pursuant to Rule 12b-1 under the Act. Under the terms of the Plan, the Fund will reimburse Federated Securities Corp. (FSC), the principal distributor, from the daily net assets of the Fund to finance activities intended to result in the sale of these shares. The Plan provides that the Fund may incur distribution expenses of up to 0.35% of average daily net assets, annually, to reimburse FSC. Subject to the terms described in the Expense Limitation note, FSC may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2015, FSC voluntarily waived its entire fee of $2,014,606. When FSC receives fees, it may pay some or all of them to financial intermediaries whose customers purchase shares.

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Expense Limitation

Due to the possibility of changes in market conditions and other factors, there can be no assurance that the level of waivers/reimbursement/reduction of Fund expenses reflected in the financial highlights will be maintained in the future. However, the Adviser and certain of its affiliates (which may include FSC, FAS and FSSC) on their own initiative have agreed to waive certain amounts of their respective fees and/or reimburse expenses. Total annual fund operating expenses (as shown in the financial highlights, excluding extraordinary expenses and proxy-related expenses paid by the Fund, if any) paid by the Fund's Shares (after the voluntary waivers and/or reimbursements) will not exceed 1.05% (the “Fee Limit”), up to but not including the later of (the “Termination Date”): (a) August 1, 2016; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its applicable affiliates currently do not anticipate terminating or increasing these arrangements prior to the Termination Date, these arrangements may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Directors.

Interfund Transactions

During the year ended May 31, 2015, the Fund engaged in purchase transactions with funds that have a common investment adviser (or affiliated investment advisers), common Directors/Trustees, and/or common Officers. These purchase transactions complied with Rule 17a-7 under the Act and amounted to $4,092,070.

General

Certain Officers and Directors of the Fund are Officers and Directors or Trustees of certain of the above companies. To efficiently facilitate payment, Directors'/Trustees' fees and certain expenses related to conducting meetings of the Directors/Trustees and other miscellaneous expenses are paid by an affiliate of the Adviser which in due course are reimbursed by the Fund. Such expenses may be included in Accrued and Miscellaneous Expenses on the Statement of Assets and Liabilities and Statement of Operations, respectively.

6. LINE OF CREDIT

The Fund participates in a $100,000,000 unsecured, uncommitted revolving line of credit (LOC) agreement with PNC Bank. The LOC was made available for extraordinary or emergency purposes, primarily for financing redemption payments. Borrowings are charged interest at a rate offered to the Fund by PNC Bank at the time of the borrowing. As of May 31, 2015, there were no outstanding loans. During the year ended May 31, 2015, the Fund did not utilize the LOC.

7. INTERFUND LENDING

Pursuant to an Exemptive Order issued by the Securities and Exchange Commission (SEC), the Fund, along with other funds advised by subsidiaries of Federated Investors, Inc., may participate in an interfund lending program. This program provides an alternative credit facility allowing the Fund to borrow from other participating affiliated funds. As of May 31, 2015, there were no outstanding loans. During the year ended May 31, 2015, the program was not utilized.

8. REGULATORY MATTERS

On July 23, 2014, the SEC voted to amend the rules under the Act which currently govern the operations of the Fund. A significant change resulting from these amendments will be a requirement that institutional prime funds (i.e. not government or retail as defined in the amendments), transact fund shares based on a market-based Net Asset Value (NAV). This change does not impact government money market funds, and because it is anticipated that

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the Fund will constitute a government money market fund under the new rules, the Fund will be permitted to continue transacting fund shares at an NAV calculated using the amortized cost valuation method. Among additional disclosure and other requirements, the amendments also will permit a money market fund, or, in certain circumstances, require a money market fund (other than a government money market fund, like the Fund, which satisfies the requirements of the amended rules) to impose liquidity fees on redemptions, and permit a money market fund to limit (or gate) redemptions for up to 10 business days in any 90-day period. The amendments have staggered compliance dates. Compliance with a majority of these amendments will be required on October 14, 2016, two years after the effective date for the rule amendments. The degree to which a money market fund will be impacted by the rule amendments will depend upon the type of fund and type of investors (retail or institutional). At this time, management is evaluating the implications of these amendments and their impact to the Fund's operations, financial statements and accompanying notes.

9. Subsequent EvenT

On June 3, 2015, the Fund filed a supplement to its current Prospectus notifying shareholders that the Directors have approved a proposed Agreement and Plan of Reorganization (Reorganization) pursuant to which Federated Trust for U.S. Treasury Obligations would acquire all or substantially all of the assets of the Fund in complete liquidation and termination of the Fund. Information statements will be sent to shareholders explaining the Reorganization. The Reorganization is expected to occur in the fourth quarter of 2015.

Management has evaluated subsequent events through the date the financial statements were issued and determined that no additional events occurred that require disclosure.

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Report of Independent Registered Public Accounting Firm

TO THE BOARD OF directors OF Cash TRUST SERIES, INC. AND SHAREHOLDERS Of Federated Treasury cash Series:

We have audited the accompanying statement of assets and liabilities of Federated Treasury Cash Series (the “Fund”) (one of the portfolios constituting Cash Trust Series, Inc.), including the portfolio of investments, as of May 31, 2015, and the related statement of operations for the year then ended, the statement of changes in net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended. These financial statements and financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

We conducted our audits in accordance with standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. We were not engaged to perform an audit of the Fund's internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements and financial highlights, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of May 31, 2015, by correspondence with the custodian and others or by other appropriate auditing procedures where replies from others were not received. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Federated Treasury Cash Series, a portfolio of Cash Trust Series, Inc., at May 31, 2015, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended, in conformity with U.S. generally accepted accounting principles.

Boston, Massachusetts
July 23, 2015

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Shareholder Expense Example (unaudited)

As a shareholder of the Fund, you incur ongoing costs, including management fees and to the extent applicable, distribution (12b-1) fees and/or other service fees and other Fund expenses. This Example is intended to help you to understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. It is based on an investment of $1,000 invested at the beginning of the period and held for the entire period from December 1, 2014 to May 31, 2015.

ACTUAL EXPENSES

The first section of the table below provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you incurred over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses attributable to your investment during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second section of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. Thus, you should not use the hypothetical account values and expenses to estimate the actual ending account balance or your expenses for the period. Rather, these figures are required to be provided to enable you to compare the ongoing costs of investing in the Fund with other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

	Beginning Account Value 12/1/2014	Ending Account Value 5/31/2015	Expenses Paid During Period1,2
Actual	$1,000	$1,000.00	$0.45
Hypothetical (assuming a 5% return before expenses)	$1,000	$1,024.48	$0.45

1

Expenses are equal to the Fund's annualized net expense ratio of 0.09%, multiplied by the average account value over the period, multiplied by 182/365 (to reflect the one-half-year period).

2

Actual and Hypothetical expenses paid during the period utilizing the Fund's current Fee Limit of 1.05% (as reflected in the Notes to Financial Statements, Note 5 under Expense Limitation), multiplied by the average account value over the period, multiplied by 182/365 (to reflect expenses paid as if they had been in effect throughout the most recent one-half-year period) would be $5.24 and $5.29, respectively.

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Board of Directors and Corporation Officers

The Board of Directors is responsible for managing the Corporation's business affairs and for exercising all the Corporation's powers except those reserved for the shareholders. The following tables give information about each Director and the senior officers of the Fund. Where required, the tables separately list Directors who are “interested persons” of the Fund (i.e., “Interested” Directors) and those who are not (i.e., “Independent” Directors). Unless otherwise noted, the address of each person listed is Federated Investors Tower, 1001 Liberty Avenue, Pittsburgh, PA 15222. The address of all Independent Directors listed is 4000 Ericsson Drive, Warrendale, PA 15086-7561; Attention: Mutual Fund Board. As of December 31, 2014, the Corporation comprised four portfolio(s), and the Federated Fund Family consisted of 40 investment companies (comprising 131 portfolios). Unless otherwise noted, each Officer is elected annually. Unless otherwise noted, each Director oversees all portfolios in the Federated Fund Family and serves for an indefinite term. The Fund's Statement of Additional Information includes additional information about Corporation Directors and is available, without charge and upon request, by calling 1-800-341-7400.

Interested DIRECTORS Background

Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years, Other Directorships Held and Previous Position(s)
John F. Donahue* Birth Date: July 28, 1924 Director Indefinite Term Began serving: May 1989	Principal Occupations: Director or Trustee of the Federated Fund Family; Chairman and Director, Federated Investors, Inc.; Chairman of the Federated Fund Family's Executive Committee. Previous Positions: Chairman of the Federated Fund Family; Trustee, Federated Investment Management Company; Chairman and Director, Federated Investment Counseling.

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Name Birth Date Positions Held with Corporation Date Service Began

Principal Occupation(s) for Past Five Years, Other Directorships Held and Previous Position(s)

J. Christopher Donahue* Birth Date: April 11, 1949 President and Director Indefinite Term Began serving: May 1989

Principal Occupations: Principal Executive Officer and President of certain of the Funds in the Federated Fund Family; Director or Trustee of the Funds in the Federated Fund Family; President, Chief Executive Officer and Director, Federated Investors, Inc.; Chairman and Trustee, Federated Investment Management Company; Trustee, Federated Investment Counseling; Chairman and Director, Federated Global Investment Management Corp.; Chairman, Federated Equity Management Company of Pennsylvania and Passport Research, Ltd. (investment advisory subsidiary of Federated); Trustee, Federated Shareholder Services Company; Director, Federated Services Company. Previous Positions: President, Federated Investment Counseling; President and Chief Executive Officer, Federated Investment Management Company, Federated Global Investment Management Corp. and Passport Research, Ltd.

* Family relationships and reasons for “interested” status: John F. Donahue is the father of J. Christopher Donahue; both are “interested” due to their beneficial ownership of shares of Federated Investors, Inc. and the positions they hold with Federated and its subsidiaries.

INDEPENDENT DIRECTORS Background

Name Birth Date Positions Held with Corporation Date Service Began

Principal Occupation(s) for Past Five Years, Other Directorships Held, Previous Position(s) and Qualifications

John T. Collins Birth Date: January 24, 1947 Director Indefinite Term Began serving: October 2013

Principal Occupations: Director or Trustee of the Federated Fund Family; Chairman and CEO, The Collins Group, Inc. (a private equity firm). Other Directorships Held: Director, Chair of the Compensation Committee, Audit Committee member, KLX Corp. Qualifications: Mr. Collins has served in several business and financial management roles and directorship positions throughout his career. Mr. Collins serves as Chairman Emeriti, Bentley University. Mr. Collins previously served as Director, FleetBoston Financial Corp.; Director and Audit Committee Member, Bank of America Corp. and Director, Beth Israel Deaconess Medical Center (Harvard University Affiliate Hospital).

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Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years, Other Directorships Held, Previous Position(s) and Qualifications
Maureen Lally-Green Birth Date: July 5, 1949 Director Indefinite Term Began serving: August 2009	Principal Occupations: Director or Trustee of the Federated Fund Family; Adjunct Professor of Law, Duquesne University School of Law. Other Directorships Held: Director, CONSOL Energy Inc. Qualifications: Judge Lally-Green has served in various legal and business roles and directorship positions throughout her career. Judge Lally-Green previously served as: Associate General Secretary, Diocese of Pittsburgh; Professor of Law, Duquesne University School of Law and was a member of the Superior Court of Pennsylvania. Judge Lally-Green also holds the positions of: Member, Pennsylvania State Board of Education; Director, Saint Vincent College; Director and Chair, UPMC Mercy Hospital; Regent, St. Vincent Seminary; Director, Epilepsy Foundation of Western and Central Pennsylvania; Director, Our Campaign for the Church Alive!, Inc.; Director, Pennsylvania Bar Institute; and Director, Catholic High Schools of the Diocese of Pittsburgh, Inc. Judge Lally-Green has held the positions of: Director, Auberle; Director, Ireland Institute of Pittsburgh; Director, Saint Thomas More Society; and Director Cardinal Wuerl Catholic High School.
Peter E. Madden Birth Date: March 16, 1942 Director Indefinite Term Began serving: August 1991	Principal Occupation: Director or Trustee, and Chair of the Board of Directors or Trustees, of the Federated Fund Family; Retired. Other Directorships Held: None. Qualifications: Mr. Madden has served in several business management, mutual fund services and directorship positions throughout his career. Mr. Madden previously served as President, Chief Operating Officer and Director, State Street Bank and Trust Company (custodian bank) and State Street Corporation (financial services). He was Director, VISA USA and VISA International and Chairman and Director, Massachusetts Bankers Association. Mr. Madden served as Director, Depository Trust Corporation and Director, The Boston Stock Exchange. Mr. Madden also served as a Representative to the Commonwealth of Massachusetts General Court.
Charles F. Mansfield, Jr. Birth Date: April 10, 1945 Director Indefinite Term Began serving: January 1999	Principal Occupations: Director or Trustee of the Federated Fund Family; Management Consultant. Other Directorships Held: None. Qualifications: Mr. Mansfield has served in several banking, business management and educational roles and directorship positions throughout his career. Mr. Mansfield previously served as Chief Executive Officer, PBTC International Bank; Partner, Arthur Young & Company (now Ernst & Young LLP); Chief Financial Officer of Retail Banking Sector, Chase Manhattan Bank; Senior Vice President, HSBC Bank USA (formerly, Marine Midland Bank); Vice President, Citibank; Assistant Professor of Banking and Finance, Frank G. Zarb School of Business, Hofstra University; Executive Vice President DVC Group, Inc. (marketing, communications and technology).

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Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years, Other Directorships Held, Previous Position(s) and Qualifications
Thomas M. O'Neill Birth Date: June 14, 1951 Director Indefinite Term Began serving: October 2006	Principal Occupations: Director or Trustee, Vice Chair of the Audit Committee of the Federated Fund Family; Sole Proprietor, Navigator Management Company (investment and strategic consulting). Other Directorships Held: None. Qualifications: Mr. O'Neill has served in several business, mutual fund and financial management roles and directorship positions throughout his career. Mr. O'Neill serves as Director, Medicines for Humanity and Director, The Golisano Children's Museum of Naples, Florida. Mr. O'Neill previously served as Chief Executive Officer and President, Managing Director and Chief Investment Officer, Fleet Investment Advisors; President and Chief Executive Officer, Aeltus Investment Management, Inc.; General Partner, Hellman, Jordan Management Co., Boston, MA; Chief Investment Officer, The Putnam Companies, Boston, MA; Credit Analyst and Lending Officer, Fleet Bank; Director and Consultant, EZE Castle Software (investment order management software); and Director, Midway Pacific (lumber).
P. Jerome Richey Birth Date: February 23, 1949 Director Indefinite Term Began serving: October 2013	Principal Occupations: Director or Trustee of the Federated Fund Family; Management Consultant. Other Directorships Held: None. Qualifications: Mr. Richey has served in several business and legal management roles and directorship positions throughout his career. Mr. Richey most recently held the positions of Senior Vice Chancellor and Chief Legal Officer, University of Pittsburgh. Mr. Richey serves as Board Member, Epilepsy Foundation of Western Pennsylvania and Board member, World Affairs Council of Pittsburgh. Mr. Richey previously served as Chief Legal Officer and Executive Vice President, CONSOL Energy Inc. and Shareholder, Buchanan Ingersoll & Rooney PC (a law firm).
John S. Walsh Birth Date: November 28, 1957 Director Indefinite Term Began serving: January 1999	Principal Occupations: Director or Trustee, Chair of the Audit Committee of the Federated Fund Family; President and Director, Heat Wagon, Inc. (manufacturer of construction temporary heaters); President and Director, Manufacturers Products, Inc. (distributor of portable construction heaters); President, Portable Heater Parts, a division of Manufacturers Products, Inc. Other Directorships Held: None. Qualifications: Mr. Walsh has served in several business management roles and directorship positions throughout his career. Mr. Walsh previously served as Vice President, Walsh & Kelly, Inc. (paving contractors).

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OFFICERS

Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years and Previous Position(s)
John W. McGonigle Birth Date: October 26, 1938 EXECUTIVE VICE PRESIDENT AND SECRETARY Officer since: May 1989	Principal Occupations: Executive Vice President and Secretary of the Federated Fund Family; Vice Chairman, Executive Vice President, Secretary and Director, Federated Investors, Inc. Previous Positions: Trustee, Federated Investment Management Company and Federated Investment Counseling; Director, Federated Global Investment Management Corp., Federated Services Company and Federated Securities Corp.
Lori A. Hensler Birth Date: January 6, 1967 TREASURER Officer since: April 2013	Principal Occupations: Principal Financial Officer and Treasurer of the Federated Fund Family; Senior Vice President, Federated Administrative Services; Financial and Operations Principal for Federated Securities Corp. and Edgewood Services, Inc.; and Assistant Treasurer, Federated Investors Trust Company. Ms. Hensler has received the Certified Public Accountant designation. Previous Positions: Controller of Federated Investors, Inc.; Senior Vice President and Assistant Treasurer, Federated Investors Management Company; Treasurer, Federated Investors Trust Company; Assistant Treasurer, Federated Administrative Services, Federated Administrative Services, Inc., Federated Securities Corp., Edgewood Services, Inc., Federated Advisory Services Company, Federated Equity Management Company of Pennsylvania, Federated Global Investment Management Corp., Federated Investment Counseling, Federated Investment Management Company, Passport Research, Ltd., and Federated MDTA, LLC; Financial and Operations Principal for Federated Securities Corp., Edgewood Services, Inc. and Southpointe Distribution Services, Inc.
Richard B. Fisher Birth Date: May 17, 1923 Vice Chairman Officer since: August 2002	Principal Occupations: Vice Chairman or Vice President of some of the Funds in the Federated Fund Family; Vice Chairman, Federated Investors, Inc.; Chairman, Federated Securities Corp. Previous Positions: President and Director or Trustee of some of the Funds in the Federated Fund Family; Executive Vice President, Federated Investors, Inc.; Director and Chief Executive Officer, Federated Securities Corp.
Peter J. Germain Birth Date: September 3, 1959 CHIEF LEGAL OFFICER Officer since: January 2005	Principal Occupations: Mr. Germain is Chief Legal Officer of the Federated Fund Family. He is General Counsel and Vice President, Federated Investors, Inc.; President, Federated Administrative Services and Federated Administrative Services, Inc.; Vice President, Federated Securities Corp.; Secretary, Federated Private Asset Management, Inc.; and Secretary, Retirement Plan Service Company of America. Mr. Germain joined Federated in 1984 and is a member of the Pennsylvania Bar Association. Previous Positions: Deputy General Counsel, Special Counsel, Managing Director of Mutual Fund Services, Federated Investors, Inc.; Senior Vice President, Federated Services Company; and Senior Corporate Counsel, Federated Investors, Inc.

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Name Birth Date Positions Held with Corporation Date Service Began	Principal Occupation(s) for Past Five Years and Previous Position(s)
Brian P. Bouda Birth Date: February 28, 1947 CHIEF COMPLIANCE OFFICER AND SENIOR VICE PRESIDENT Officer since: August 2004; Retiring July 29, 2015	Principal Occupations: Senior Vice President and Chief Compliance Officer of the Federated Fund Family; Vice President and Chief Compliance Officer of Federated Investors, Inc. and Chief Compliance Officer of certain of its subsidiaries. Mr. Bouda joined Federated in 1999 and is a member of the American Bar Association and the State Bar Association of Wisconsin. Previous Positions: Served in Senior Management positions with a large regional banking organization.
Stephen Van Meter Birth Date: June 5, 1975 CHIEF COMPLIANCE OFFICER AND SENIOR VICE PRESIDENT Officer since: Effective July 30, 2015	Principal Occupations: Senior Vice President and Chief Compliance Officer of the Federated Fund Family; Vice President and Chief Compliance Officer of Federated Investors, Inc. and Chief Compliance Officer of certain of its subsidiaries. Mr. Van Meter joined Federated in October 2011. He holds FINRA licenses under Series 3, 7, 24 and 66. Previous Positions: Mr. Van Meter previously held the position of Compliance Operating Officer, Federated Investors, Inc. Prior to joining Federated, Mr. Van Meter served at the United States Securities and Exchange Commission in the positions of Senior Counsel, Office of Chief Counsel, Division of Investment Management and Senior Counsel, Division of Enforcement.
Deborah A. Cunningham Birth Date: September 15, 1959 Chief Investment Officer Officer since: May 2004	Principal Occupations: Deborah A. Cunningham was named Chief Investment Officer of Federated's money market products in 2004. She joined Federated in 1981 and has been a Senior Portfolio Manager since 1997 and an Executive Vice President of the Fund's Adviser since 2009. Ms. Cunningham has received the Chartered Financial Analyst designation and holds an M.S.B.A. in Finance from Robert Morris College.
Susan R. Hill Birth Date: June 20, 1963 VICE PRESIDENT Officer since: June 2012 Portfolio Manager since: January 1994	Principal Occupations: Susan R. Hill has been the Fund's Portfolio Manager since January 1994. She is Vice President of the Corporation with respect to the Fund. Ms. Hill joined Federated in 1990 and has been a Senior Portfolio Manager since 2003 and a Senior Vice President of the Fund's Adviser since 2005. Ms. Hill was a Portfolio Manager from 1994 until 2003 and served as Vice President of the Fund's Adviser from 1997 until 2004 and an Assistant Vice President of the Fund's Adviser from 1994 until 1997. Ms. Hill has received the Chartered Financial Analyst designation and holds an M.S. in Industrial Administration from Carnegie Mellon University.

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Evaluation and Approval of Advisory Contract–May 2015

Federated Treasury Cash Series (the “Fund”)

Following a review and recommendation of approval by the Fund's independent directors, the Fund's Board reviewed and approved at its May 2015 meetings the Fund's investment advisory contract for an additional one-year term. The Board's decision regarding the contract reflects the exercise of its business judgment on whether to continue the existing arrangements.

In this connection, the Federated Funds' Board had previously appointed a Senior Officer, whose duties include specified responsibilities relating to the process by which advisory fees are to be charged to a Federated fund. The Senior Officer has the authority to retain consultants, experts, or staff as may be reasonably necessary to assist in the performance of his duties, reports directly to the Board, and may be terminated only with the approval of a majority of the independent members of the Board. The Senior Officer prepared and furnished to the Board an independent, written evaluation that covered topics discussed below (the “Evaluation”). The Board considered that Evaluation, along with other information, in deciding to approve the advisory contract.

The Board is also familiar with and considered judicial decisions concerning allegedly excessive investment advisory fees, which have indicated that the following factors may be relevant to an Adviser's fiduciary duty with respect to its receipt of compensation from a fund: the nature and quality of the services provided by the Adviser to a fund and its shareholders, including the performance and expenses of the fund and of comparable funds; the Adviser's cost of providing the services, including the profitability to the Adviser of providing advisory services to a fund; the extent to which the Adviser may realize “economies of scale” as a fund grows larger and, if such economies of scale exist, whether they have been shared with a fund and its shareholders or the family of funds; any “fall-out financial benefits” that accrue to the Adviser because of its relationship with a fund (including research services received from brokers that execute fund trades and any fees paid to affiliates of the Adviser for services rendered to a fund); comparative fee structures, including a comparison of fees paid to the Adviser with those paid by similar funds; and the extent of care, conscientiousness and independence with which the Board members perform their duties and their expertise, including whether they are fully informed about all facts the Board deems relevant to its consideration of the Adviser's services and fees. The Board noted that SEC disclosure requirements regarding the basis for the Board's approval of the Fund's advisory contract generally track the factors listed above. Consistent with these judicial decisions and SEC disclosure requirements, the Board also considered management fees

Annual Shareholder Report

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charged to institutional and other clients of the Adviser for what might be viewed as like services. The Board was aware of these factors and was guided by them in its review of the Fund's advisory contract to the extent it considered them to be appropriate and relevant, as discussed further below.

The Board considered and weighed these circumstances in light of its substantial accumulated experience in governing the Fund and working with Federated on matters relating to the Federated funds, and was assisted in its deliberations by independent legal counsel. Throughout the year, and in connection with its May meetings, the Board requested and received substantial and detailed information about the Fund and the Federated organization that was in addition to the extensive materials that comprise and accompany the Senior Officer's Evaluation. Federated provided much of this information at each regular meeting of the Board, and furnished additional substantial information in connection with the May meeting at which the Board's formal review of the advisory contract occurred. At this May meeting, senior management of the Adviser also met with the independent directors and their counsel to discuss the materials presented and any other matters thought relevant by the Adviser or the directors. Between regularly scheduled meetings, the Board also received information on particular matters as the need arose. Thus, the Board's consideration of the advisory contract included review of the Senior Officer's Evaluation, accompanying data and additional information covering such matters as: the Adviser's investment philosophy, revenue, profitability, personnel and processes; investment and operating strategies; the Fund's short- and long-term performance (in absolute terms, both on a gross basis and net of expenses, as well as in relationship to its particular investment program and certain competitor or “peer group” funds and/or other benchmarks, as appropriate), and comments on the reasons for performance; the Fund's investment objectives; the Fund's expenses (including the advisory fee itself and the overall expense structure of the Fund, both in absolute terms and relative to similar and/or competing funds, with due regard for contractual or voluntary expense limitations); the use and allocation of brokerage commissions derived from trading the Fund's portfolio securities (if any); and the nature, quality and extent of the advisory and other services provided to the Fund by the Adviser and its affiliates. The Board also considered the preferences and expectations of Fund shareholders; the entrepreneurial risk assumed by the Adviser in sponsoring the funds; the continuing state of competition in the mutual fund industry and market practices; the range of comparable fees for similar funds in the mutual fund industry; the Fund's relationship to the Federated family of funds which include a comprehensive array of funds with different investment objectives, policies and strategies which are available for exchange without the incurrence of additional sales charges; compliance and audit reports concerning the Federated funds and the Federated companies that service them (including communications from regulatory agencies), as well as Federated's responses to any issues raised therein; and relevant developments in

Annual Shareholder Report

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the mutual fund industry and how the Federated funds and/or Federated are responding to them. The Board's evaluation process is evolutionary. The criteria considered and the emphasis placed on relevant criteria change in recognition of changing circumstances in the mutual fund marketplace.

While mindful that courts have cautioned against giving such comparisons too much weight, the Board has found the use of comparisons of the Fund's fees and expenses to other mutual funds with comparable investment programs to be relevant. In this regard, the Board was presented with, and considered, information regarding the contractual advisory fee rates, net advisory fee rates and total expense ratios relative to a fund's peers. The Board focused on comparisons with other similar mutual funds more heavily than non-mutual fund products or services because it is believed that they are more relevant. For example, other mutual funds are the products most like the Fund, they are readily available to Fund shareholders as alternative investment vehicles, and they are the type of investment vehicle in fact chosen and maintained by the Fund's investors. The range of their fees and expenses therefore appears to be a relevant indicator of what consumers have found to be reasonable in the precise marketplace in which the Fund competes.

It was noted in the materials for the Board meeting that for the period covered by the Evaluation, the Fund's investment advisory fee was waived in its entirety. The Board reviewed the contractual advisory fee rate, net advisory fee rate and other expenses of the Fund with the Adviser and noted the position of the Fund's fee rates relative to its peers. In this regard, the Board noted that the contractual advisory fee rate was above the median of the relevant peer group, but the Board noted that the investment advisory fee was waived in its entirety and that the overall expense structure of the Fund remained competitive.

By contrast, the Senior Officer has reviewed Federated's fees for providing advisory services to products outside the Federated family of funds (e.g., institutional and separate accounts and sub-adviser services). He concluded that mutual funds and institutional accounts are inherently different products. Those differences include, but are not limited to, different types of targeted investors; being subject to different laws and regulations; different legal structures; different average account sizes and portfolio management techniques made necessary by different cash flows and different associated costs; and the time spent by portfolio managers and their teams, funds financial services, legal, compliance and risk management in reviewing securities pricing, addressing different administrative responsibilities, addressing different degrees of risk associated with management and a variety of different costs. The Senior Officer did not consider these fee schedules to be determinative in judging the appropriateness of mutual fund advisory fees.

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The Fund's ability to deliver competitive performance when compared to its peer group was also deemed to be relevant by the Board as a useful indicator of how the Adviser is executing the Fund's investment program, which in turn was one of the Board's considerations in reaching a conclusion that the nature, extent, and quality of the Adviser's investment management services were such as to warrant continuation of the advisory contract.

The Senior Officer reviewed information compiled by Federated, using data supplied by independent fund ranking organizations, regarding the performance of, and fees charged by, other mutual funds, noting his view that comparisons to fund peer groups may be helpful, though not conclusive, in judging the reasonableness of the proposed fees. The Board considered, in evaluating such comparisons, that in some cases individual funds may exhibit significant and unique differences in their objectives and management techniques when compared to other funds within an industry peer group.

The Fund's performance was above the median of the relevant peer group for the one-year period covered by the Evaluation.

The Board also received financial information about Federated, including information regarding the compensation and benefits Federated derived from its relationships with the Federated funds. This information covered not only the fees under the advisory contracts, but also fees received by Federated's subsidiaries for providing other services to the Federated funds under separate contracts (e.g., for serving as the Federated funds' administrator). The information also detailed any indirect benefit Federated may derive from its receipt of research services from brokers who execute Federated fund trades. In addition, the Board considered the fact that, in order for a fund to be competitive in the marketplace, Federated and its affiliates frequently waived fees and/or reimbursed expenses and have disclosed to fund investors and/or indicated to the Board their intention to do so in the future, where appropriate. Moreover, the Board receives regular reporting as to the institution, adjustment or elimination of these voluntary waivers.

In addition, over the past two years, following discussions regarding the Senior Officer's recommendations, Federated made meaningful reductions to the contractual advisory fees for several Funds. In May 2014, the Senior Officer recommended that Federated review the fee structures of its money market funds to determine whether it would be appropriate to consider alternative pricing structures. Federated has combined that review with its consideration of the re-structuring of its money market fund product line in response to the recently adopted amendments to Rule 2a-7 under the Investment Company Act of 1940, as amended (the “1940 Act”).

At the Board meeting in May 2015, following previous recommendations of the Senior Officer, Federated proposed, and the Board approved, reductions in the contractual advisory fees of certain other Funds.

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Federated furnished information, requested by the Senior Officer, that reported revenues on a fund-by-fund basis and made estimates of the allocation of expenses on a fund-by-fund basis, using allocation methodologies specified by the Senior Officer. The Senior Officer noted that, while these cost allocation reports apply consistent allocation processes, the inherent difficulties in allocating costs continues to cause the Senior Officer to question the precision of the process and to conclude that such reports may be unreliable, since a single change in an allocation estimate may dramatically alter the resulting estimate of cost and/or profitability of a fund and may produce unintended consequences. The allocation information, including the Senior Officer's view that fund-by-fund estimations may be unreliable, was considered in the analysis by the Board.

The Board and the Senior Officer also reviewed information compiled by Federated comparing profitability information for Federated to other publicly held fund management companies. In this regard, the Senior Officer concluded that Federated's profit margins did not appear to be excessive. The Senior Officer also noted that Federated appeared financially sound, with the resources to fulfill its obligations under its contracts with the Funds.

The Senior Officer's Evaluation also discussed the notion of possible realization of “economies of scale” as a fund grows larger. The Board considered in this regard that the Adviser has made significant and long-term investments in areas that support all of the Federated family of funds, such as personnel and processes for the portfolio management, shareholder services, compliance, internal audit, and risk management functions; and systems technology; and that the benefits of these efforts (as well as any economies of scale, should they exist) were likely to be enjoyed by the fund family as a whole. Federated, as it does throughout the year, and again in connection with the Board's review, furnished information relative to revenue sharing or adviser paid fees. Federated and the Senior Officer noted that this information should be viewed to determine if there was an incentive to either not apply breakpoints or to apply breakpoints at higher levels and should not be viewed to determining the appropriateness of advisory fees, because it would represent marketing and distribution expenses. Finally, the Board also noted the absence of any applicable regulatory or industry guidelines on this subject, which (as discussed in the Senior Officer's Evaluation) is compounded by the lack of any common industry practice or general pattern with respect to structuring fund advisory fees with “breakpoints” that serve to reduce the fee as the fund attains a certain size.

The Senior Officer noted that, subject to the comments and recommendations made within his Evaluation, his observations and the information accompanying the Evaluation supported a finding by the Board that the management fees for each of the funds were reasonable. Under these circumstances, no objection was raised to the continuation of, the Fund's advisory contract.

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In its decision to continue an existing investment advisory contract, the Board was mindful of the potential disruptions of the Fund's operations and various risks, uncertainties and other effects that could occur as a result of a decision to terminate or not renew an advisory contract. In particular, the Board recognized that many shareholders have invested in the Fund on the strength of the Adviser's industry standing and reputation and with the expectation that the Adviser will have a continuing role in providing advisory services to the Fund. Thus, the Board's approval of the advisory contract reflected the fact that it is the shareholders who have effectively selected the Adviser by virtue of having invested in the Fund. The Board concluded that, in light of the factors discussed above, including the nature, quality and scope of the services provided to the Fund by the Adviser and its affiliates, continuation of the advisory contract was appropriate.

The Board based its decision to approve the advisory contract on the totality of the circumstances and relevant factors and with a view to past and future long-term considerations. Not all of the factors and considerations identified above were necessarily relevant to the Fund, nor did the Board consider any one of them to be determinative. With respect to the factors that were relevant, the Board's decision to approve the contract reflects its determination that Federated's performance and actions provided a satisfactory basis to support the decision to continue the existing arrangements.

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Voting Proxies on Fund Portfolio Securities

A description of the policies and procedures that the Fund uses to determine how to vote proxies, if any, relating to securities held in the Fund's portfolio is available, without charge and upon request, by calling 1-800-341-7400. A report on “Form N-PX” of how the Fund voted any such proxies during the most recent 12-month period ended June 30 is available via the Proxy Voting Record (Form N-PX) link associated with the Fund and share class name at www.FederatedInvestors.com/FundInformation. Form N-PX filings are also available at the SEC's website at www.sec.gov.

Quarterly Portfolio Schedule

The Fund files with the SEC a complete schedule of its portfolio holdings, as of the close of the first and third quarters of its fiscal year, on “Form N-Q.” These filings are available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, DC. (Call 1-800-SEC-0330 for information on the operation of the Public Reference Room.) You may also access this information via the link to the Fund and share class name at www.FederatedInvestors.com/FundInformation.

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Mutual funds are not bank deposits or obligations, are not guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency. Investment in mutual funds involves investment risk, including the possible loss of principal. Although money market funds seek to maintain a stable net asset value of $1.00 per share, there is no assurance that they will be able to do so.

This Report is authorized for distribution to prospective investors only when preceded or accompanied by the Fund's Prospectus, which contains facts concerning its objective and policies, management fees, expenses and other information.

Federated Treasury Cash Series
Federated Investors Funds
4000 Ericsson Drive
Warrendale, PA 15086-7561

Contact us at FederatedInvestors.com
or call 1-800-341-7400.

Federated Securities Corp., Distributor

CUSIP 147551402

28567 (7/15)

Federated is a registered trademark of Federated Investors, Inc.
2015 ©Federated Investors, Inc.

Item 2. Code of Ethics

(a) As of the end of the period covered by this report, the registrant has adopted a code of ethics (the "Section 406 Standards for Investment Companies - Ethical Standards for Principal Executive and Financial Officers") that applies to the registrant's Principal Executive Officer and Principal Financial Officer; the registrant's Principal Financial Officer also serves as the Principal Accounting Officer.

(c) There was no amendment to the registrant’s code of ethics described in Item 2(a) above during the period covered by the report.

(d) There was no waiver granted, either actual or implicit, from a provision to the registrant’s code of ethics described in Item 2(a) above during the period covered by the report.

(e) Not Applicable

(f)(3) The registrant hereby undertakes to provide any person, without charge, upon request, a copy of the code of ethics. To request a copy of the code of ethics, contact the registrant at 1-800-341-7400, and ask for a copy of the Section 406 Standards for Investment Companies - Ethical Standards for Principal Executive and Financial Officers.

Item 3. Audit Committee Financial Expert

The registrant's Board has determined that each of the following members of the Board's Audit Committee is an “audit committee financial expert,” and is "independent," for purposes of this Item:   Charles F. Mansfield, Jr., Thomas M. O'Neill and John S. Walsh.

Item 4. Principal Accountant Fees and Services

(a) Audit Fees billed to the registrant for the two most recent fiscal years:

Fiscal year ended 2015 - $80,050

Fiscal year ended 2014 - $80,050

(b) Audit-Related Fees billed to the registrant for the two most recent fiscal years:

Fiscal year ended 2015 - $0

Fiscal year ended 2014 - $60

Fiscal year ended 2014- Travel to Audit Committee Meeting.

Amount requiring approval of the registrant’s audit committee pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X, $0 and $0 respectively.

(c) Tax Fees billed to the registrant for the two most recent fiscal years:

Fiscal year ended 2015 - $0

Fiscal year ended 2014 - $0

Amount requiring approval of the registrant’s audit committee pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X, $ 0 and $ 0 respectively.

(d) All Other Fees billed to the registrant for the two most recent fiscal years:

Fiscal year ended 2015 - $0

Fiscal year ended 2014 - $0

Amount requiring approval of the registrant’s audit committee pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X, $0 and $0 respectively.

(e)(1) Audit Committee Policies regarding Pre-approval of Services.

The Audit Committee is required to pre-approve audit and non-audit services performed by the independent auditor in order to assure that the provision of such services do not impair the auditor’s independence. Unless a type of service to be provided by the independent auditor has received general pre-approval, it will require specific pre-approval by the Audit Committee. Any proposed services exceeding pre-approved cost levels will require specific pre-approval by the Audit Committee.

Certain services have the general pre-approval of the Audit Committee. The term of the general pre-approval is 12 months from the date of pre-approval, unless the Audit Committee specifically provides for a different period. The Audit Committee will annually review the services that may be provided by the independent auditor without obtaining specific pre-approval from the Audit Committee and may grant general pre-approval for such services. The Audit Committee will revise the list of general pre-approved services from time to time, based on subsequent determinations. The Audit Committee will not delegate its responsibilities to pre-approve services performed by the independent auditor to management.

The Audit Committee has delegated pre-approval authority to its Chairman. The Chairman will report any pre-approval decisions to the Audit Committee at its next scheduled meeting. The Committee will designate another member with such pre-approval authority when the Chairman is unavailable.

AUDIT SERVICES

The annual Audit services engagement terms and fees will be subject to the specific pre-approval of the Audit Committee. The Audit Committee must approve any changes in terms, conditions and fees resulting from changes in audit scope, registered investment company (RIC) structure or other matters.

In addition to the annual Audit services engagement specifically approved by the Audit Committee, the Audit Committee may grant general pre-approval for other Audit Services, which are those services that only the independent auditor reasonably can provide. The Audit Committee has pre-approved certain Audit services, all other Audit services must be specifically pre-approved by the Audit Committee.

AUDIT-RELATED SERVICES

Audit-related services are assurance and related services that are reasonably related to the performance of the audit or review of the Company’s financial statements or that are traditionally performed by the independent auditor. The Audit Committee believes that the provision of Audit-related services does not impair the independence of the auditor, and has pre-approved certain Audit-related services, all other Audit-related services must be specifically pre-approved by the Audit Committee.

TAX SERVICES

The Audit Committee believes that the independent auditor can provide Tax services to the Company such as tax compliance, tax planning and tax advice without impairing the auditor’s independence. However, the Audit Committee will not permit the retention of the independent auditor in connection with a transaction initially recommended by the independent auditor, the purpose of which may be tax avoidance and the tax treatment of which may not be supported in the Internal Revenue Code and related regulations. The Audit Committee has pre-approved certain Tax services, all Tax services involving large and complex transactions must be specifically pre-approved by the Audit Committee.

ALL OTHER SERVICES

With respect to the provision of services other than audit, review or attest services the pre-approval requirement is waived if:

(1) The aggregate amount of all such services provided constitutes no more than five percent of the total amount of revenues paid by the registrant, the registrant’s adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant to its accountant during the fiscal year in which the services are provided;

(2) Such services were not recognized by the registrant, the registrant’s adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant at the time of the engagement to be non-audit services; and

(3) Such services are promptly brought to the attention of the Audit Committee of the issuer and approved prior to the completion of the audit by the Audit Committee or by one or more members of the Audit Committee who are members of the board of directors to whom authority to grant such approvals has been delegated by the Audit Committee.

The Audit Committee may grant general pre-approval to those permissible non-audit services classified as All Other services that it believes are routine and recurring services, and would not impair the independence of the auditor.

The SEC’s rules and relevant guidance should be consulted to determine the precise definitions of prohibited non-audit services and the applicability of exceptions to certain of the prohibitions.

PRE-APPROVAL FEE LEVELS

Pre-approval fee levels for all services to be provided by the independent auditor will be established annually by the Audit Committee. Any proposed services exceeding these levels will require specific pre-approval by the Audit Committee.

PROCEDURES

Requests or applications to provide services that require specific approval by the Audit Committee will be submitted to the Audit Committee by both the independent auditor and the Principal Accounting Officer and/or Internal Auditor, and must include a joint statement as to whether, in their view, the request or application is consistent with the SEC’s rules on auditor independence.

(e)(2) Percentage of services identified in items 4(b) through 4(d) that were approved by the registrants audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X:

4(b)

Fiscal year ended 2015 – 0%

Fiscal year ended 2014 - 0%

Percentage of services provided to the registrants investment adviser and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were approved by the registrants audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X, 0% and 0% respectively.

4(c)

Fiscal year ended 2015 – 0%

Fiscal year ended 2014 – 0%

Percentage of services provided to the registrants investment adviser and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were approved by the registrants audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X, 0% and 0% respectively.

4(d)

Fiscal year ended 2015 – 0%

Fiscal year ended 2014 – 0%

Percentage of services provided to the registrants investment adviser and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were approved by the registrants audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X, 0% and 0% respectively.

(f) NA

(g) Non-Audit Fees billed to the registrant, the registrant’s investment adviser, and certain entities controlling, controlled by or under common control with the investment adviser:

Fiscal year ended 2015 - $76,974

Fiscal year ended 2014 - $94,892

(h) The registrant’s Audit Committee has considered that the provision of non-audit services that were rendered to the registrant’s adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were not pre-approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X is compatible with maintaining the principal accountant’s independence.

Item 5. Audit Committee of Listed Registrants

Not Applicable

Item 6. Schedule of Investments

(a) The registrant’s Schedule of Investments is included as part of the Report to Stockholders filed under Item 1 of this form.

(b) Not Applicable; Fund had no divestments during the reporting period covered since the previous Form N-CSR filing.

Item 7. Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies

Not Applicable

Item 8. Portfolio Managers of Closed-End Management Investment Companies

Not Applicable

Item 9. Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers

Not Applicable

Item 10. Submission of Matters to a Vote of Security Holders

No Changes to Report

Item 11. Controls and Procedures

(a) The registrant’s President and Treasurer have concluded that the

registrant’s disclosure controls and procedures (as defined in rule 30a-3(c) under the Act) are effective in design and operation and are sufficient to form the basis of the certifications required by Rule 30a-(2) under the Act, based on their evaluation of these disclosure controls and procedures within 90 days of the filing date of this report on Form N-CSR.

(b) There were no changes in the registrant’s internal control over financial reporting (as defined in rule 30a-3(d) under the Act) during the second fiscal quarter of the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 12. Exhibits

(a)(1) Code of Ethics- Not Applicable to this Report.

(a)(2) Certifications of Principal Executive Officer and Principal Financial Officer.

(a)(3) Not Applicable.

(b) Certifications pursuant to 18 U.S.C. Section 1350.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Registrant Cash Trust Series, Inc.

By /S/ Lori A. Hensler

Lori A. Hensler

Principal Financial Officer

Date July 23, 2015

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By /S/ J. Christopher Donahue

J. Christopher Donahue

Principal Executive Officer

Date July 23, 2015

By /S/ Lori A. Hensler

Lori A. Hensler

Principal Financial Officer

Date July 23, 2015