UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  FORM N-CSRS

                   CERTIFIED SHAREHOLDER REPORT OF REGISTERED
                         MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number: 811-09713

Active Assets Institutional Money Trust
                    (Exact name of registrant as specified in charter)

1221 Avenue of the Americas, New York, New York 10020
      (Address of principal executive offices)                        (Zip code)

Ronald E. Robison
1221 Avenue of the Americas, New York, New York 10020
                    (Name and address of agent for service)

Registrant's telephone number, including area code: 212-762-4000

Date of fiscal year end: June 30, 2004

Date of reporting period: December 31, 2003

Item 1 - Report to Shareholders


Welcome, Shareholder:

In this report, you'll learn about how your investment in Active Assets
Institutional Money Trust performed during the semiannual period. We will
provide an overview of the market conditions, and discuss some of the factors
that affected performance during the reporting period. In addition, this report
includes the Fund's financial statements and a list of Fund investments.

This material must be preceded or accompanied by a prospectus for the fund being
offered. Market forecasts provided in this report may not necessarily come to
pass. There is no assurance that the Fund will achieve its investment objective.
The Fund is subject to market risk, which is the possibility that market values
of securities owned by the Fund will decline and, therefore, the value of the
Fund's shares may be less than what you paid for them. Accordingly, you can lose
money investing in this Fund.


FUND REPORT

For the six-month period ended December 31, 2003

MARKET CONDITIONS


The Federal Open Market Committee (the "Fed") lowered its target rate for
federal funds to 1.00 percent, a 45-year low, on June 25, 2003. It maintained
that target throughout the second half of the year to encourage a faster pace of
economic activity. By the second half of 2003 the combination of this highly
accommodative monetary posture and stimulative fiscal policies in the form of
tax cuts appeared to begin to have an effect, with many companies reporting
improved second-half earnings and the third-quarter GDP increasing to 8.2
percent. The Fed's sustained emphasis on low interest rates had a marked impact
on money market fund yields, which reached record low levels during the period.

PERFORMANCE ANALYSIS


As of December 31, 2003, Active Assets Institutional Money Trust had net assets
of more than $1.0 billion and the average maturity of the Fund's portfolio was
45 days. For the six-month period ended December 31, 2003, the Fund returned
0.46 percent. For the seven-day period ended December 31, 2003, the Fund
provided an effective annualized yield, and a current yield, both of 0.92
percent, while its 30-day moving average yield for December was likewise 0.92
percent. Past performance is no guarantee of future results.

Our strategy in managing the Fund remained consistent with our long-term focus
on maintaining preservation of capital and very high liquidity.* As we have in
the past, we adhered to a conservative approach that avoided the use of
derivatives or structured notes that might fluctuate excessively with changing
interest rates. On December 31, 2003, approximately 55 percent of the Fund's
portfolio was invested in high-quality commercial paper, 15 percent in federal
agency obligations, 18 percent in certificates of deposit issued by financially
strong commercial banks and the remaining 12 percent in an overnight repurchase
agreement. At the end of the fiscal period, approximately 85 percent of the
Fund's holdings were due to mature in less than four months.
- ----------------------------------------------------
*  An investment in the Fund is not insured or guaranteed by the Federal Deposit
   Insurance Corporation or any other government agency. Although the Fund seeks
   to preserve the value of your investment at $1.00 per share, it is possible
   to lose money by investing in the Fund.

2


<Table>
<Caption>
   PORTFOLIO COMPOSITION
                                                 
   Commercial Paper                                    55.6%
   Certificates of Deposit                             17.7
   U.S. Government Agencies                            14.7
   Repurchase Agreement                                12.0
</Table>

<Table>
<Caption>
   MATURITY SCHEDULE
                                                 
     1 - 30 Days                                       60.1%
    31 - 60 Days                                       14.8
    61 - 90 Days                                        7.7
    91 - 120 Days                                       3.1
   121+ Days                                           14.3
</Table>

Subject to change daily. All percentages are as a percentage of total
investments. Provided for informational purposes only and should not be deemed
as a recommendation to buy or sell the securities mentioned. Morgan Stanley is a
full-service securities firm engaged in securities trading and brokerage
activities, investment banking, research and analysis, financing and financial
advisory services.

INVESTMENT STRATEGY


1) THE FUND INVESTS IN HIGH QUALITY, SHORT-TERM DEBT OBLIGATIONS.

2) IN SELECTING INVESTMENTS, THE FUND'S "INVESTMENT MANAGER," MORGAN STANLEY
   INVESTMENT ADVISORS INC., SEEKS TO MAINTAIN THE FUND'S SHARE PRICE AT $1.00.
   THE SHARE PRICE REMAINING STABLE AT $1.00 MEANS THAT THE FUND WOULD PRESERVE
   THE PRINCIPAL VALUE OF YOUR INVESTMENT.

                                                                               3


Active Assets Institutional Money Trust
PORTFOLIO OF INVESTMENTS - DECEMBER 31, 2003 (UNAUDITED)

<Table>
<Caption>
                                                                          ANNUALIZED
PRINCIPAL                           DESCRIPTION                              YIELD
AMOUNT IN                               AND                               ON DATE OF
THOUSANDS                          MATURITY DATES                          PURCHASE          VALUE
- -------------------------------------------------------------------------------------------------------
                                                                               
            Commercial Paper (55.6%)
            Banking (4.9%)
$ 20,000    Bank of America Corp.
              05/05/04..................................................    1.14%       $   19,922,156
  30,000    Citicorp
              01/14/04..................................................     1.08           29,989,200
                                                                                        --------------
                                                                                            49,911,356
                                                                                        --------------
            Finance - Automotive (5.4%)
  15,000    DaimlerChrysler Revolving Auto Conduit
              01/21/04..................................................     1.10           14,991,292
  40,000    New Center Asset Trust
              01/08/04 - 03/17/04.......................................  1.08 - 1.09       39,961,708
                                                                                        --------------
                                                                                            54,953,000
                                                                                        --------------
            Finance - Consumer (7.4%)
  15,000    Barton Capital Corp. - 144A*
              01/09/04..................................................     1.09           14,996,821
  18,000    Old Line Funding Corp. - 144A*
              01/05/04..................................................     1.09           17,998,365
  41,900    Sheffield Rec. Corp. - 144A*
              01/05/04 - 01/22/04.......................................  1.07 - 1.09       41,885,165
                                                                                        --------------
                                                                                            74,880,351
                                                                                        --------------
            Finance - Corporate (4.0%)
  40,000    CAFCO, LLC - 144A*
              01/23/04..................................................     1.08           39,974,800
                                                                                        --------------

            Financial Conglomerates (12.7%)
  51,000    General Electric Capital Corp.
              01/27/04 - 05/06/04.......................................  1.08 - 1.18       50,908,750
  45,000    Mortgage Interest Networking Trust
              01/05/04 - 02/20/04.......................................  1.08 - 1.09       44,964,553
  21,000    Preferred Receivables Funding Corp. - 144A*
              01/05/04..................................................     1.09           20,998,092
  12,000    Yorktown Capital LLC - 144A*
              01/16/04..................................................     1.09           11,994,913
                                                                                        --------------
                                                                                           128,866,308
                                                                                        --------------
            Integrated Oil (2.0%)
  20,000    Shell Finance Oil (U.K.) PLC
              03/08/04..................................................     1.11           19,959,667
                                                                                        --------------
</Table>

4
                       See Notes to Financial Statements


Active Assets Institutional Money Trust
PORTFOLIO OF INVESTMENTS - DECEMBER 31, 2003 (UNAUDITED) continued

<Table>
<Caption>
                                                                          ANNUALIZED
PRINCIPAL                           DESCRIPTION                              YIELD
AMOUNT IN                               AND                               ON DATE OF
THOUSANDS                          MATURITY DATES                          PURCHASE          VALUE
- -------------------------------------------------------------------------------------------------------
                                                                               
            International Banks (19.2%)
$ 20,000    BNP Paribas Finance Inc.
              01/15/04..................................................    1.09%       $   19,992,164
  25,000    Canadian Imperial Holdings Inc.
              02/04/04..................................................     1.09           24,975,021
  40,000    CBA (Delaware) Finance Inc.
              01/07/04..................................................     1.07           39,994,055
  20,000    Dexia Delaware LLC
              01/21/04..................................................     1.08           19,988,600
  15,000    ING (U.S.) Funding LLC
              01/12/04..................................................     1.08           14,995,500
  30,000    Societe Generale N.A. Inc.
              02/05/04..................................................     1.08           29,969,400
  45,000    Toronto-Dominion Holdings (U.S.A.), Inc.
              01/02/04 - 02/02/04.......................................  1.08 - 1.09       44,971,842
                                                                                        --------------
                                                                                           194,886,582
                                                                                        --------------
            Total Commercial Paper (Cost $563,432,064)...............................      563,432,064
                                                                                        --------------
            Certificates of Deposit (17.7%)
  25,000    BNP Paribas, New York Branch
              01/20/04..................................................     1.09           25,000,000
  15,000    Bank of America, N.A.
              03/15/04..................................................     1.10           15,000,000
  20,000    Citibank, N.A.
              02/19/04..................................................     1.10           20,000,000
  25,000    Lloyds TSB Bank PLC, New York Branch
              01/30/04..................................................     1.07           25,000,193
  47,000    Rabobank Nederland, New York Branch
              06/21/04 - 06/22/04.......................................  1.10 - 1.11       47,000,000
  22,000    Royal Bank of Scotland PLC, New York Branch
              05/07/04..................................................     1.12           22,001,478
  25,000    UBS AG, Stamford Branch
              07/01/04..................................................     1.10           25,000,000
                                                                                        --------------
            Total Certificates of Deposit (Cost $179,001,671)........................      179,001,671
                                                                                        --------------
</Table>

                                                                               5
                       See Notes to Financial Statements


Active Assets Institutional Money Trust
PORTFOLIO OF INVESTMENTS - DECEMBER 31, 2003 (UNAUDITED) continued

<Table>
<Caption>
                                                                          ANNUALIZED
PRINCIPAL                           DESCRIPTION                              YIELD
AMOUNT IN                               AND                               ON DATE OF
THOUSANDS                          MATURITY DATES                          PURCHASE          VALUE
- -------------------------------------------------------------------------------------------------------
                                                                               
            U.S. Government Agencies (14.7%)
$ 25,000    Federal Home Loan Banks
              01/30/04..................................................    1.09%       $   24,979,000
  62,841    Federal National Mortgage Assoc.
              01/07/04 - 06/02/04.......................................  1.01 - 1.10       62,713,088
  62,000    Freddie Mac
              01/09/04 - 04/22/04.......................................  1.06 - 1.15       61,860,251
                                                                                        --------------
            Total U.S. Government Agencies (Cost $149,552,339).......................      149,552,339
                                                                                        --------------
            Repurchase Agreement (12.0%)
 121,240    Goldman, Sachs & Co.
              due 01/02/04 (dated 12/31/03; proceeds $121,246,870) (a)
              (Cost $121,240,000).......................................     1.02          121,240,000
                                                                                        --------------
            Total Investments (Cost $1,013,226,074) (b)..................  100.0%        1,013,226,074

            Other Assets in Excess of Liabilities........................     0.0               85,527
                                                                            -----       --------------
            Net Assets...................................................  100.0%       $1,013,311,601
                                                                            =====       ==============
</Table>

- ---------------------

<Table>
  
*    Resale is restricted to qualified institutional investors.
(a)  Collateralized by Federal National Mortgage Assoc. 5.50% due
     11/01/33 valued at $123,664,801.
(b)  Cost is the same for federal income tax purposes.
</Table>

6
                       See Notes to Financial Statements


Active Assets Institutional Money Trust
FINANCIAL STATEMENTS

Statement of Assets and Liabilities
December 31, 2003 (unaudited)

<Table>
                                 
Assets:
Investments in securities, at
  value (including a repurchase
  agreement of $121,240,000)
  (cost $1,013,226,074)...........  $1,013,226,074
Cash..............................           3,212
Interest receivable...............         231,684
Prepaid expenses..................          73,899
                                    --------------
    Total Assets..................   1,013,534,869
                                    --------------
Liabilities:
Payable for:
    Investment management fee.....         137,456
    Dividends to shareholders.....          50,731
Accrued expenses..................          35,081
                                    --------------
    Total Liabilities.............         223,268
                                    --------------
    Net Assets....................  $1,013,311,601
                                    ==============
Composition of Net Assets:
Paid-in-capital...................  $1,013,202,301
Accumulated undistributed net
  investment income...............         109,300
                                    --------------
    Net Assets....................  $1,013,311,601
                                    ==============
Net Asset Value Per Share,
1,013,311,601 shares outstanding
(unlimited authorized shares of
$.01 par value)...................           $1.00
                                    ==============
</Table>

Statement of Operations
For the six months ended December 31, 2003 (unaudited)

<Table>
                                     
Net Investment Income:
Interest Income.......................  $6,610,304
                                        ----------
Expenses
Investment management fee.............     915,855
Shareholder reports and notices.......      35,650
Custodian fees........................      24,376
Professional fees.....................      23,009
Registration fees.....................      14,194
Trustees' fees and expenses...........       7,449
Transfer agent fees and expenses......       1,553
Other.................................      21,504
                                        ----------
    Total Expenses....................   1,043,590
                                        ----------
    Net Investment Income.............   5,566,714
    Net Realized Gain.................         746
                                        ----------
Net Increase..........................  $5,567,460
                                        ==========
</Table>

                                                                               7
                       See Notes to Financial Statements


Active Assets Institutional Money Trust
FINANCIAL STATEMENTS continued

Statement of Changes in Net Assets

<Table>
<Caption>
                                                                 FOR THE SIX       FOR THE YEAR
                                                                MONTHS ENDED          ENDED
                                                              DECEMBER 31, 2003   JUNE 30, 2003
                                                              -----------------   --------------
                                                                 (unaudited)
                                                                            
Increase (Decrease) in Net Assets:
Operations:
Net investment income.......................................   $    5,566,714     $   16,141,230
Net realized gain...........................................              746              8,900
                                                               --------------     --------------
    Net Increase............................................        5,567,460         16,150,130
                                                               --------------     --------------
Dividends and Distributions to Shareholders from:
Net investment income.......................................       (5,566,714)       (16,141,230)
Net realized gain...........................................             (746)            (8,900)
                                                               --------------     --------------
    Total Dividends and Distributions.......................       (5,567,460)       (16,150,130)
                                                               --------------     --------------

Net decrease from transactions in shares of beneficial
  interest..................................................     (135,153,915)        (4,293,399)
                                                               --------------     --------------
    Net Decrease............................................     (135,153,915)        (4,293,399)
Net Assets:
Beginning of period.........................................    1,148,465,516      1,152,758,915
                                                               --------------     --------------
End of Period
(Including accumulated undistributed net investment income
of $109,300 and $109,300, respectively).....................   $1,013,311,601     $1,148,465,516
                                                               ==============     ==============
</Table>

8
                       See Notes to Financial Statements


Active Assets Institutional Money Trust
NOTES TO FINANCIAL STATEMENTS - DECEMBER 31, 2003 (UNAUDITED)

1. Organization and Accounting Policies

Active Assets Institutional Money Trust (the "Fund") is registered under the
Investment Company Act of 1940, as amended (the "Act"), as a diversified,
open-end management investment company. The Fund's investment objective is high
current income, preservation of capital and liquidity. The Fund was organized as
a Massachusetts business trust on November 23, 1999 and commenced operations on
February 15, 2000.

The following is a summary of significant accounting policies:

A. Valuation of Investments -- Portfolio securities are valued at amortized
cost, which approximates market value.

B. Accounting for Investments -- Security transactions are accounted for on the
trade date (date the order to buy or sell is executed). Realized gains and
losses on security transactions are determined by the identified cost method.
Discounts are accreted and premiums are amortized over the life of the
respective securities. Interest income is accrued daily.

C. Repurchase Agreements -- The Fund may invest directly with institutions in
repurchase agreements. The Fund's custodian receives the collateral, which is
marked-to-market daily to determine that the value of the collateral does not
decrease below the repurchase price plus accrued interest.

D. Federal Income Tax Policy -- It is the Fund's policy to comply with the
requirements of the Internal Revenue Code applicable to regulated investment
companies and to distribute substantially all of its taxable income to its
shareholders. Accordingly, no federal income tax provision is required.

E. Dividends and Distributions to Shareholders -- The Fund records dividends and
distributions to shareholders as of the close of each business day.

F. Use of Estimates -- The preparation of financial statements in accordance
with generally accepted accounting principles requires management to make
estimates and assumptions that affect the reported amounts and disclosures.
Actual results could differ from those estimates.

2. Investment Management Agreement

Pursuant to an Investment Management Agreement with Morgan Stanley Investment
Advisors Inc. (the "Investment Manager"), the Fund pays the Investment Manager a
management fee, accrued daily and payable monthly, by applying the annual rate
of 0.15% to the net assets of the Fund determined as of the close of each
business day.

The Investment Manager has agreed to reimburse all operating expenses and to
waive the compensation provided for in its Investment Management Agreement to
the extent that such

                                                                               9


Active Assets Institutional Money Trust
NOTES TO FINANCIAL STATEMENTS - DECEMBER 31, 2003 (UNAUDITED) continued

expenses and compensation on an annualized basis exceed 0.20% of the daily net
assets of the Fund.

3. Security Transactions and Transactions with Affiliates

The cost of purchases and proceeds from sales/maturities of portfolio securities
for the six months ended December 31, 2003, aggregated $23,093,772,650, and
$23,233,536,276, respectively.

Morgan Stanley Trust, an affiliate of the Investment Manager, is the Fund's
transfer agent.

4. Shares of Beneficial Interest

Transactions in shares of beneficial interest, at $1.00 per share, were as
follows:

<Table>
<Caption>
                                                                 FOR THE SIX       FOR THE YEAR
                                                                MONTHS ENDED          ENDED
                                                              DECEMBER 31 2003    JUNE 30, 2003
                                                              -----------------   --------------
                                                                 (unaudited)
                                                                            

Shares sold.................................................    1,901,189,827      4,177,514,450
Shares issued in reinvestment of dividends and
  distributions.............................................        5,550,486         16,254,374
                                                               --------------     --------------
                                                                1,906,740,313      4,193,768,824
Shares redeemed.............................................   (2,041,894,228)    (4,198,062,223)
                                                               --------------     --------------
Net decrease in shares outstanding..........................     (135,153,915)        (4,293,399)
                                                               ==============     ==============
</Table>

5. Legal Matters

The Investment Manager, certain affiliates of the Investment Manager and certain
investment companies advised by the Investment Manager or its affiliates,
including the Fund, are named as defendants in a number of recently filed,
similar class action complaints. These complaints generally allege that
defendants, including the Fund, violated their statutory disclosure obligations
and fiduciary duties by failing properly to disclose (i) that the Investment
Manager and certain affiliates of the Investment Manager allegedly offered
economic incentives to brokers and others to steer investors to the funds
advised by the Investment Manager or its affiliates rather than funds managed by
other companies, and (ii) that the funds advised by the Investment Manager or
its affiliates, including the Fund, allegedly paid excessive commissions to
brokers in return for their alleged efforts to steer investors to these funds.
The complaints seek, among other things, unspecified compensatory damages,
rescissionary damages, fees and costs. The defendants intend to move to dismiss
these actions and otherwise vigorously to defend them. While the Fund believes
that it has meritorious defenses, the ultimate outcome of these matters is not
presently determinable at this early stage of the litigation, and no provision
has been made in the Fund's financial statements for the effect, if any, of
these matters.

10


Active Assets Institutional Money Trust
FINANCIAL HIGHLIGHTS

Selected ratios and per share data for a share of beneficial interest
outstanding throughout each period:

<Table>
<Caption>
                                                                                                               FOR THE PERIOD
                                          FOR THE SIX                 FOR THE YEAR ENDED JUNE 30,            FEBRUARY 15, 2000*
                                         MONTHS ENDED             ------------------------------------            THROUGH
                                       DECEMBER 31, 2003            2003          2002          2001           JUNE 30, 2000
                                       -----------------          --------      --------      --------       ------------------
                                          (unaudited)
                                                                                              
Selected Per Share Data:

Net asset value, beginning of
 period..............................        $ 1.00                $ 1.00       $  1.00       $  1.00             $  1.00
                                             ------                ------       -------       -------             -------

Net income from investment
 operations..........................         0.005                 0.014         0.024         0.058               0.023

Less dividends from net investment
 income..............................        (0.005)+              (0.014)+      (0.024)+      (0.058)+            (0.023)
                                             ------                ------       -------       -------             -------

Net asset value, end of period.......        $ 1.00                $ 1.00       $  1.00       $  1.00             $  1.00
                                             ======                ======       =======       =======             =======

Total Return.........................          0.46%(1)              1.37%         2.45%         5.95%               2.31%(1)

Ratios to Average Net Assets:
Expenses.............................          0.17%(2)              0.17%         0.17%         0.19%               0.20%(2)(3)

Net investment income................          0.91%(2)              1.36%         2.40%         5.61%               6.12%(2)(3)

Supplemental Data:
Net assets, end of period, in
 millions............................        $1,013                $1,148        $1,153        $1,146                $813
</Table>

- ---------------------

<Table>
  
 *   Commencement of operations.
 +   Includes capital gain distribution of less than $0.001.
(1)  Not annualized.
(2)  Annualized.
(3)  If the Fund had borne all of its expenses that were
     reimbursed or waived by the Investment Manager, the
     annualized expense and net investment income ratios would
     have been 0.31% and 6.01%, respectively.
</Table>

                                                                              11
                       See Notes to Financial Statements


TRUSTEES

Michael Bozic
Charles A. Fiumefreddo
Edwin J. Garn
Wayne E. Hedien
James F. Higgins
Dr. Manuel H. Johnson
Joseph J. Kearns
Michael E. Nugent
Philip J. Purcell
Fergus Reid

OFFICERS

Charles A. Fiumefreddo
Chairman of the Board

Mitchell M. Merin
President

Ronald E. Robison
Executive Vice President and Principal Executive Officer

Barry Fink
Vice President and General Counsel

Joseph J. McAlinden
Vice President

Stefanie V. Chang
Vice President

Francis J. Smith
Treasurer and Chief Financial Officer

Thomas F. Caloia
Vice President

Mary E. Mullin
Secretary

TRANSFER AGENT

Morgan Stanley Trust
Harborside Financial Center, Plaza Two
Jersey City, New Jersey 07311

INDEPENDENT AUDITORS

Deloitte & Touche LLP
Two World Financial Center
New York, New York 10281

INVESTMENT ADVISOR

Morgan Stanley Investment Advisors Inc.
1221 Avenue of the Americas
New York, New York 10020

The financial statements included herein have been taken from the records of the
Fund without examination by the independent auditors and accordingly they do not
express an opinion thereon.

This report is submitted for the general information of shareholders of the
Fund. For more detailed information about the Fund, its fees and expenses and
other pertinent information, please read its Prospectus. The Fund's Statement of
Additional Information contains additional information about the Fund, including
its trustees. It is available, without charge, by calling (800) 869-NEWS.

This report is not authorized for distribution to prospective investors in the
Fund unless preceded or accompanied by an effective Prospectus. Read the
Prospectus carefully before investing.

Investments and services offered through Morgan Stanley DW Inc., member SIPC.

(c) 2003 Morgan Stanley

[MORGAN STANLEY LOGO]

MORGAN STANLEY FUNDS

Active Assets
Institutional
Money Trust

Semiannual Report
December 31, 2003

[MORGAN STANLEY LOGO]

13678B04-AP-2/04


Item 2. Code of Ethics.

Not applicable for semiannual reports.

Item 3. Audit Committee Financial Expert.

Not applicable for semiannual reports.

Item 4. Principal Accountant Fees and Services

Not applicable for semiannual reports.

Item 5. Audit Committee of Listed Registrants.

Not applicable for semiannual reports.

Item 6. [Reserved.]

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

Not applicable for semiannual reports.

Item 8. [Reserved.]

Item 9 - Controls and Procedures

(a) The Fund's principal executive officer and principal financial officer have
concluded that the Fund's disclosure controls and procedures are sufficient to
ensure that information required to be disclosed by the Fund in this Form N-CSR
was recorded, processed, summarized and reported within the time periods
specified in the Securities and Exchange Commission's rules and forms, based
upon such officers' evaluation of these controls and procedures as of a date
within 90 days of the filing date of the report.

         There were no significant changes or corrective actions with regard to
significant deficiencies or material weaknesses in the Fund's internal controls
or in other factors that could significantly affect the Fund's internal controls
subsequent to the date of their evaluation.



(b) There were no changes in the registrant's internal control over financial
reporting that occurred during the registrant's most recent fiscal half-year
(the registrant's second fiscal half-year in the case of an annual report) that
has materially affected, or is reasonably likely to materially affect, the
registrant's internal control over financial reporting.

Item 10 Exhibits

(a) Code of Ethics - Not applicable for semiannual reports.

(b) A separate certification for each principal executive officer and principal
financial officer of the registrant are attached hereto as part of EX-99.CERT.

                                       2



                                   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.

Active Assets Institutional Money Trust

/s/ Ronald E. Robison
Ronald E. Robison
Principal Executive Officer
February 18, 2004

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

/s/ Ronald E. Robison
Ronald E. Robison
Principal Executive Officer
February 18, 2004

/s/ Francis Smith
Francis Smith
Principal Financial Officer
February 18, 2004

                                       3