1

                                                Filed pursuant to Rule 424(b)(1)
                                                 Registration File No. 333-55906

PROSPECTUS

                                  $200,000,000

                               IES UTILITIES INC.
[ALLIANT LOGO]

                   6 3/4% SERIES B SENIOR DEBENTURES DUE 2011
                             ---------------------
- - We are a public utility engaged primarily in the generation, transmission,
  distribution and sale of electric energy and the purchase, transportation,
  distribution and sale of natural gas.

- - We are offering $200,000,000 of our unsecured senior debentures that will rank
  on parity with our other unsecured and unsubordinated debt.

- - The senior debentures are due on March 15, 2011. We will pay interest on the
  senior debentures twice per year, on March 15 and September 15 of each year,
  beginning on September 15, 2001.

- - We may redeem the senior debentures at any time at our option, in whole or in
  part, at a redemption price equal to the sum of the principal amount of the
  senior debentures we redeem, accrued interest on that principal amount to the
  redemption date and the make-whole amount.

- - The senior debentures will not be listed on any securities exchange or
  included in any automated quotation system.
                             ---------------------
NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED THESE SECURITIES OR DETERMINED IF THIS
PROSPECTUS IS ACCURATE OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.
                             ---------------------



                                                                   PER
                                                                 SENIOR
                                                                DEBENTURE               TOTAL
                                                                ---------               -----
                                                                               
Public offering price.......................................     99.762%             $199,524,000
Underwriting discount.......................................      0.650%             $  1,300,000
Proceeds to us (before expenses)............................     99.112%             $198,224,000


     Accrued interest, if any, from the date of issuance will be added to the
public offering price set forth above. The proceeds to us do not deduct expenses
of the offering that we must pay, which we estimate will be approximately
$265,000.

     The senior debentures are offered by the several underwriters when, as and
if delivered to and accepted by them subject to various prior conditions,
including their right to reject orders in whole or in part. We expect that the
senior debentures will be ready for delivery in book-entry form through The
Depository Trust Company on or about March 12, 2001.
                             ---------------------
                              JOINT LEAD MANAGERS

LEGG MASON WOOD WALKER                                       MERRILL LYNCH & CO.
         INCORPORATED
                             ---------------------

ROBERT W. BAIRD & CO.
                        UTENDAHL CAPITAL PARTNERS, L.P.
                                                       WACHOVIA SECURITIES, INC.

                 The date of this prospectus is March 6, 2001.
   2

                               IES UTILITIES INC.

     We are an Iowa corporation, an operating public utility and a subsidiary of
Alliant Energy Corporation. We generate, transmit, distribute and sell electric
energy; purchase, transport, distribute and sell natural gas; and provide steam
services. Our service area has an estimated population of 1,161,000, all within
the State of Iowa.

     As of December 31, 2000, we furnished retail electric service to
approximately 347,000 customers in 525 cities, villages and towns. We also
supplied wholesale electric service to five customers. During the nine-month
period ended September 30, 2000, we derived our electric operating revenues from
the following types of customers:

     - residential -- 37%

     - commercial -- 28%

     - industrial -- 29%

     - sales for resale -- 4%

     - other -- 2%.

     The maximum net hourly peak load on our electric system in the year ended
December 31, 2000 was 2,067 megawatts. At the time of the peak load on our
system, we had the capacity to provide up to 2,143 megawatts of electricity,
including 1,916 megawatts of generated capacity and 227 megawatts of purchased
capacity under contract. During 2000, our net kilowatt-hour sources of
electricity consisted of the following:

     - coal -- 52%

     - nuclear -- 26%

     - purchases -- 18%

     - natural gas -- 3%

     - other -- 1%.

     As of December 31, 2000, we provided retail natural gas service to
approximately 182,000 customers in 212 cities, villages and towns. During the
nine-month period ended September 30, 2000, we derived our gas operating
revenues from the following types of customers:

     - residential -- 60%

     - commercial -- 29%

     - industrial -- 8%

     - transportation and other -- 3%.

     We are subject to the jurisdiction of the Iowa Utilities Board with respect
to various phases of our operations. We are also subject to the jurisdiction of
the Federal Energy Regulatory Commission. Our parent company, Alliant Energy
Corporation, is a registered public utility holding company under the Public
Utility Holding Company Act of 1935 and is subject to the requirements of that
Act. We are also subject to some requirements of that Act.

     Our tariffs provide for subsequent adjustments to our electric and natural
gas rates for changes in the cost of fuel, purchased energy and natural gas
purchased for resale. Our purchased capacity costs are not recovered from
electric customers through energy adjustment clauses. Recovery of these costs
must be addressed in base rates in a formal rate proceeding.

     Our principal executive offices are located at Alliant Energy Tower, 200
First Street, SE, Cedar Rapids, Iowa 52401, and our telephone number is (319)
398-4411.
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MERGER WITH INTERSTATE POWER COMPANY

     On March 15, 2000, we entered into an agreement and plan of merger with
Interstate Power Company. Interstate Power Company is also an operating public
utility and a subsidiary of Alliant Energy. Interstate Power Company generates,
transmits, distributes and sells electric energy and purchases, transports,
distributes and sells natural gas in more than 10,000 square miles in the states
of Iowa, Minnesota and Illinois.

     The merger agreement provides for:

     - Interstate Power Company to merge with and into us;

     - us to survive the merger; and

     - our new name to be "Interstate Power and Light Company."

     We expect that the combined company will reduce corporate and
administrative expenses by reducing systems costs related to redundant reporting
requirements. In addition, we expect the combined company to realize savings by
eliminating some redundant maintenance contracts.

     We expect the merger to qualify as a common control merger for accounting
and financial reporting purposes. The accounting for a common control merger is
similar to a pooling of interests. For accounting and financial reporting
purposes, we will be treated as if we had always been combined with Interstate
Power Company. The merger is intended to be tax-free for federal income tax
purposes.

     The merger agreement has been approved by our board of directors and the
board of directors of Interstate Power Company. The merger is still subject to
the approval of the merger agreement by several federal and state regulatory
agencies and by our preferred shareowners and by Interstate Power Company's
preferred shareowners and its sole common shareowner, Alliant Energy, voting
together as a single class. We and Interstate Power Company have each scheduled
a special meeting of our respective shareowners to consider approval of the
merger agreement on April 3, 2001. Alliant Energy beneficially owns 92.8% of the
aggregate voting power of all Interstate Power Company shareowners and intends
to vote for approval of the merger agreement. As a result, approval of the
merger agreement by the Interstate Power Company shareowners is assured.

     If you would like more information about Interstate Power Company or the
merger, then you should read our proxy statement/prospectus included in our
registration statement on Form S-4/A, filed with the Securities and Exchange
Commission on February 12, 2001. See "Where You Can Find More Information."

RECENT DEVELOPMENTS

     The following information for the year ended December 31, 2000 has been
derived from our and Interstate Power Company's preliminary unaudited results of
operations. See "Where You Can Find More Information."

     IES Utilities. Our earnings available for common stock increased 12.2% to
$73.5 million on operating revenues of $876.0 million for the year ended
December 31, 2000 compared to earnings available for common stock of $65.5
million on operating revenues of $800.7 million for the year ended December 31,
1999. Our operating income increased 3.9% to $167.8 million, or 19.2% of
operating revenues, for the year ended December 31, 2000 compared to $161.5
million, or 20.2% of operating revenues, for the year ended December 31, 1999.

     The increase in our earnings available for common stock and our operating
income was primarily due to reduced other operation and maintenance expenses,
higher electric and gas margins and lower tax expense primarily due to a lower
effective income tax rate. Those changes were partially offset by higher
depreciation and amortization expense due to property additions. Higher interest
income, largely due to a tax settlement realized in 2000, also contributed to
the increase in earnings available for common stock.

                                        2
   4

     Reduced other operation and maintenance expenses were primarily due to
lower energy efficiency expenses and reduced administrative and general expenses
resulting from expenses incurred in 1999 relating to our Year 2000 readiness
program and lower employee benefit costs. Such decreases were partially offset
by higher nuclear operation costs and one-time fees related to the transfer from
the Mid-Continent Area Power Pool reliability region to the Mid-America
Interconnected Network, Inc. region. Electric margin increased due to increased
sales resulting from economic growth, partially offset by the impact of a 1999
change in estimate of the utility services rendered but unbilled at month-end,
milder weather and reduced recoveries for Iowa-mandated energy efficiency
programs. Gas margin increased primarily due to increased sales resulting from
colder weather in the fourth quarter of 2000.

     Interstate Power Company. Interstate Power Company's earnings available for
common stock decreased 7.7% to $26.2 million on operating revenues of $358.0
million for the year ended December 31, 2000 compared to earnings available for
common stock of $28.4 million on operating revenues of $342.1 million for the
year ended December 31, 1999. Interstate Power Company's operating income
decreased 7.5% to $56.8 million, or 15.9% of operating revenues, for the year
ended December 31, 2000 compared to $61.4 million, or 17.9% of operating
revenues, for the year ended December 31, 1999.

     The decrease in Interstate Power Company's earnings available for common
stock and its operating income was primarily due to increased other operation
and maintenance expenses, higher depreciation and amortization expense due to
property additions and lower gas margin. Those changes were partially offset by
higher electric margin. The changes' effect on earnings available for common
stock was also partially offset by reduced income tax expense due to a lower
effective income tax rate.

     The increase in other operation and maintenance expenses was primarily due
to increased energy efficiency expenditures and higher transmission and
distribution expenses. Such increases were partially offset by expenses incurred
in 1999 relating to Interstate Power Company's Year 2000 readiness program and
reduced employee benefit costs. The lower gas margin resulted from reduced
sales. The increased electric margin was primarily due to higher sales resulting
from economic growth, increased capacity sales and higher recoveries for energy
efficiency programs. These items were partially offset by a 1999 change in
estimate of utility services rendered but unbilled at month-end and milder
weather.

     Pro Forma. The pro forma combined earnings available for common stock of us
and Interstate Power Company, giving effect to the proposed merger, increased
6.2% to $99.7 million on pro forma combined operating revenues of $1,234.0
million for the year ended December 31, 2000 compared to pro forma combined
earnings available for common stock of $93.9 million on pro forma combined
operating revenues of $1,142.8 million for the year ended December 31, 1999. Pro
forma combined operating income increased 0.8% to $224.6 million, or 18.2% of
pro forma combined operating revenues, for the year ended December 31, 2000
compared to $222.9 million, or 19.5% of pro forma combined operating revenues,
for the year ended December 31, 1999.

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   5

                                USE OF PROCEEDS

     We intend to use $81.6 million of the net proceeds from the sale of the
senior debentures to repay our outstanding long-term indebtedness that matures
at or prior to July 1, 2001 as it comes due. We intend to use the remaining
proceeds to repay short-term indebtedness. As of January 31, 2001, we had $81.6
million in long-term debt outstanding that will mature at or prior to July 1,
2001 at a weighted-average annual interest rate of 8.73%. In addition, we had
$108.0 million in short-term debt outstanding at a weighted bond equivalent
yield rate of 6.37%. We will add any proceeds that we do not use for those
purposes to our general funds and use them for general corporate purposes.

                                 CAPITALIZATION



                                                                 AT SEPTEMBER 30, 2000 (UNAUDITED)
                                                          ------------------------------------------------
                                                                                             AS ADJUSTED
                                                                        AS ADJUSTED FOR      FOR MERGER
                                                            ACTUAL          MERGER         AND OFFERING(1)
                                                            ------      ---------------    ---------------
                                                                       (THOUSANDS OF DOLLARS)
                                                                                  
First Mortgage Bonds..................................    $  111,000      $  255,000         $  174,000
Collateral Trust Bonds................................       234,400         234,400            234,400
Pollution Control Obligations.........................        22,900          52,050             51,490
Senior Debentures.....................................       135,000         135,000            335,000
Subordinated Deferrable Interest Debentures...........        50,000          50,000             50,000
Unamortized Debt Premium and (Discount), net..........        (2,032)         (4,804)            (4,804)
Preferred Stock with Mandatory Redemption.............            --          24,650             24,650
Preferred Stock without Mandatory Redemption..........        18,320          29,139             29,139
Common Shareowners' Investment........................       580,786         808,883            808,883
                                                          ----------      ----------         ----------
  Total...............................................    $1,150,374      $1,584,318         $1,702,758
                                                          ==========      ==========         ==========


- -------------------------
(1) We have adjusted these numbers to show the effects of the issuance of the
    senior debentures and the application of the net proceeds as we describe
    under "Use of Proceeds."

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                         SUMMARY FINANCIAL INFORMATION

HISTORICAL IES UTILITIES INFORMATION

     We have set forth below summary financial information about us for the nine
months ended September 30, 2000 and 1999, and the years ended December 31, 1999,
1998 and 1997. We derived the information set forth below from our consolidated
financial statements and related notes. You should read the following
information in conjunction with our Management's Discussion and Analysis of
Financial Condition and Results of Operations and our consolidated financial
statements and related notes, which are incorporated into this prospectus by
reference. See "Where You Can Find More Information."



                                             NINE MONTHS
                                         ENDED SEPTEMBER 30,                     YEAR ENDED
                                             (UNAUDITED)                        DECEMBER 31,
                                       ------------------------    --------------------------------------
                                          2000          1999          1999          1998          1997
                                          ----          ----          ----          ----          ----
                                                             (THOUSANDS OF DOLLARS)
                                                                                
Income Statement Data:
  Operating Revenues...............    $  624,999    $  608,386    $  800,696    $  806,930    $  813,978
  Operating Income.................    $  133,822    $  132,355    $  161,499    $  154,996    $  153,770
  Earnings Available for Common
     Stock.........................    $   59,331    $   56,293    $   65,532    $   60,996    $   57,879
Balance Sheet Data at End of
  Period:
  Total Assets.....................    $1,756,243    $1,740,586    $1,755,808    $1,788,978    $1,768,929


HISTORICAL INTERSTATE POWER COMPANY INFORMATION

     We have set forth below summary financial information about Interstate
Power Company for the nine months ended September 30, 2000 and 1999, and the
years ended December 31, 1999, 1998 and 1997. We derived the information set
forth below from Interstate Power Company's financial statements and related
notes. You should read the following information in conjunction with Interstate
Power Company's Management's Discussion and Analysis of Financial Condition and
Results of Operations and its financial statements and related notes, which are
incorporated into this prospectus by reference. See "Where You Can Find More
Information."



                                                  NINE MONTHS
                                              ENDED SEPTEMBER 30,                YEAR ENDED
                                                  (UNAUDITED)                   DECEMBER 31,
                                              --------------------    --------------------------------
                                                2000        1999        1999        1998        1997
                                                ----        ----        ----        ----        ----
                                                               (THOUSANDS OF DOLLARS)
                                                                               
Income Statement Data:
  Operating Revenues......................    $261,138    $264,904    $342,105    $355,889    $331,847
  Operating Income........................    $ 47,778    $ 50,283    $ 61,363    $ 45,490    $ 55,500
  Earnings Available for Common Stock.....    $ 19,902    $ 23,471    $ 28,364    $ 16,282    $ 26,698
Balance Sheet Data at End of Period:
  Total Assets............................    $675,106    $650,887    $662,184    $657,363    $643,447


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UNAUDITED PRO FORMA COMBINED INFORMATION

     We have set forth below unaudited summary pro forma combined financial
information that combines the historical balance sheets and statements of income
of us and Interstate Power Company, giving effect to the proposed merger. We
derived the information set forth below from the consolidated financial
statements and related notes of us and Interstate Power Company. The unaudited
pro forma combined income statement information gives effect to the proposed
merger as if it had occurred on January 1, 1999. The unaudited pro forma
combined balance sheet information gives effect to the proposed merger as if it
had occurred on September 30, 2000. You should read the following information in
conjunction with the unaudited pro forma combined financial statements and
related notes, which are incorporated into this prospectus by reference. See
"Where You Can Find More Information."



                                                                    NINE MONTHS
                                                                ENDED SEPTEMBER 30,
                                                                    (UNAUDITED)           YEAR ENDED
                                                               ----------------------    DECEMBER 31,
                                                                  2000         1999          1999
                                                                  ----         ----      ------------
                                                                       (THOUSANDS OF DOLLARS)
                                                                                
Income Statement Data:
  Operating Revenues.......................................    $  886,137    $873,290     $1,142,801
  Operating Income.........................................    $  181,600    $182,638     $  222,862
  Earnings Available for Common Stock......................    $   79,233    $ 79,764     $   93,896
Balance Sheet Data at End of Period:
  Total Assets.............................................    $2,431,302


                      RATIOS OF EARNINGS TO FIXED CHARGES

     The following table sets forth our ratios of earnings to fixed charges for
the periods presented:



                                                  NINE MONTHS
                                                     ENDED                 YEAR ENDED DECEMBER 31,
                                                 SEPTEMBER 30,    -----------------------------------------
                                                     2000         1999     1998     1997     1996     1995
                                                 -------------    ----     ----     ----     ----     ----
                                                                                    
IES Utilities................................            3.46x    3.08x    2.83x    2.77x    3.23x    3.04x
Interstate Power Company.....................            4.01x    4.22x    2.96x    3.90x    3.75x    3.69x
Pro Forma Combined...........................            3.59x    3.33x    2.86x    3.02x    3.37x    3.21x


When we computed the ratios of earnings to fixed charges, we calculated earnings
by adding net income plus income taxes, plus interest expense, plus an estimate
of the interest component of rent expense. Fixed charges represent interest
expense and the estimated interest component of rent expense.

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                      DESCRIPTION OF THE SENIOR DEBENTURES

GENERAL

     The 6 3/4% Series B Senior Debentures due 2011 offered in this prospectus
constitute our unsecured general obligations, and they will rank on parity with
all of our other unsecured and unsubordinated debt. We will issue the senior
debentures as a separate series of securities under the indenture, dated as of
August 1, 1997, between us and Bank One Trust Company, National Association, as
successor to The First National Bank of Chicago, as trustee. The indenture does
not limit the aggregate principal amount of senior unsecured debt securities
that we can issue under it, and provides that we may issue securities from time
to time in one or more series pursuant to the terms of one or more supplemental
indentures, board resolutions or officers' certificates creating the series. The
indenture also does not limit the total amount of debt that we can incur under
other instruments. As of the date of this prospectus, we had $135.0 million of
securities outstanding under the indenture, consisting solely of our 6 5/8%
Series A Senior Debentures due 2009. The indenture does not limit our ability to
issue additional first mortgage bonds. It also does not give holders of the
senior debentures protection in the event we engage in a highly leveraged or
other transaction that may adversely affect holders of the senior debentures.

     Our indentures and deeds of trust securing our first mortgage bonds are
direct first mortgage liens upon substantially all of our tangible public
utility property. Our indentures and deeds of trust securing our collateral
trust bonds are direct second liens on substantially all of our tangible public
utility property while our first mortgage bonds remain outstanding. As of the
date of this prospectus, we had $111.0 million of first mortgage bonds and
$234.4 million of collateral trust bonds outstanding. In addition, as of the
date of this prospectus, Interstate Power Company had $144.0 million of first
mortgage bonds outstanding. If we complete the proposed merger, then the
Interstate Power Company first mortgage bonds will become our obligation and the
related indenture will also be a lien on substantially all of our tangible
public utility property. If we become bankrupt, liquidate or reorganize, the
trustees for the first mortgage bonds and collateral trust bonds could use the
collateral property to satisfy our obligations under the first mortgage bonds
and collateral trust bonds before holders of unsecured debt securities,
including the senior debentures, would receive any payments.

     We have summarized below various provisions of the indenture and the senior
debentures. Because this discussion is only a summary, it does not necessarily
contain all of the information you should consider. We have filed the indenture
as an exhibit to the registration statement, and we incorporate the indenture by
reference into this prospectus. See "Where You Can Find More Information." We
qualify the discussion below in its entirety by reference to all of the
provisions of the indenture and all supplemental indentures, board resolutions
or officers' certificates relating thereto.

MATURITY AND INTEREST

     We are offering the senior debentures in the aggregate principal amount of
$200 million. The senior debentures will mature on March 15, 2011. Each senior
debenture will bear interest from March 12, 2001 or from and including the most
recent interest payment date to which we have paid interest, at the rate of
6 3/4% per year. We will pay interest twice per year, on March 15 and September
15, commencing September 15, 2001, to the persons in whose names the senior
debentures are registered at the close of business (1) on the business day prior
to each interest payment date if the senior debentures remain in book-entry only
form or (2) on the fifteenth calendar day before each interest payment date if
the senior debentures do not remain in book-entry only form.

REDEMPTION PRIOR TO MATURITY

     We may redeem the senior debentures at any time at our option, in whole or
in part, at a redemption price equal to the sum of the principal amount of the
senior debentures we redeem, accrued interest on that principal amount to the
redemption date and the make-whole amount, if any, with respect to those senior
debentures. This sum is referred to as the redemption price.

                                        7
   9

     "Make-whole amount" means, in connection with the optional redemption, the
excess, if any, of:

     - the aggregate present value as of the date of any optional redemption of
       each dollar of principal being redeemed and the amount of interest,
       exclusive of interest accrued to the date of redemption, that would have
       been payable in respect of such dollar of principal if such redemption
       had not been made, determined by discounting, on a semi-annual basis,
       such principal and interest at the reinvestment rate, as determined on
       the third business day preceding the date that notice of the redemption
       is given, from the respective dates on which such principal and interest
       would have been payable if such redemption had not been made, over

     - the aggregate principal amount of the senior debentures being redeemed.

     "Reinvestment rate" means 0.25% plus the arithmetic mean of the yields
under the respective headings "This Week" and "Last Week" published in the
statistical release under the caption "Treasury Constant Maturities" for the
maturity, rounded to the nearest month, corresponding to the remaining life to
maturity, as of the payment date of the principal being redeemed. If no maturity
exactly corresponds to such maturity, yields for the two published maturities
most closely corresponding to such maturity will be calculated pursuant to the
immediately preceding sentence and the reinvestment rate will be interpolated or
extrapolated from such yields on a straight-line basis, rounding in each of the
relevant periods to the nearest month. For purposes of calculating the
reinvestment rate, the most recent statistical release published prior to the
date of determination of the make-whole amount will be used.

     "Statistical release" means the statistical release designated "K.15(519)"
or any successor publication which is published weekly by the Federal Reserve
System and which establishes yields on actively traded United States government
securities adjusted to constant maturities or, if such statistical release is
not published at the time of any determination, then such other reasonably
comparable index which shall be designated by us.

     No sinking fund will be established for the benefit of the senior
debentures.

LIMITATIONS ON LIENS

     The covenant we describe below is the only restrictive covenant that
applies to the senior debentures. If we issue additional series of securities
under the indenture in the future, those series may or may not have different
covenants. Most obligations we have under the indenture and the senior
debentures are subject to termination if we exercise our defeasance rights,
which we describe below under "Defeasance."

     The indenture provides generally that, as long as any securities of any
series to which this limitation applies, including the senior debentures, remain
outstanding, we will not, and will not permit any of our subsidiaries to, create
or allow to be created or to exist any lien on any of our properties or assets
to secure any indebtedness, without making effective a provision that makes the
senior debentures and the other securities of any series to which this
limitation applies equally and ratably secured with or prior to all such
indebtedness and with any other indebtedness that is also entitled to be equally
secured. This restriction does not apply to or prevent the creation or existence
of:

     - the indentures and deeds of trust securing our first mortgage bonds or
       collateral bonds;

     - liens on property that existed when we acquired or built the property or
       were created within one year after that time;

     - liens on property that secure payment of all or a part of the purchase
       price or construction cost of the property, including the extension of
       any such liens to repairs or improvements made on the property;

     - any extensions, renewals or replacements of liens permitted by the
       above-listed items;

     - the pledge of any bonds or other securities at any time issued under any
       of the liens permitted by the above-listed items; or

                                        8
   10

     - "Permitted Liens," which include, among several other things:

      # the pledge or assignment in the ordinary course of business of
        electricity, gas or steam accounts receivable or customers' installment
        paper; and

      # liens not otherwise permitted if, at the time we incur the lien and
        after giving effect to the lien, the aggregate of all obligations
        secured by the lien does not exceed 10% of our tangible net worth, as
        defined in the indenture.

     This restriction does not limit our ability to enter into sale and
leaseback transactions with respect to any of our property. Also, this
restriction will not apply to or prevent the creation or existence of leases we
enter into, or existing on property we acquire, in the ordinary course of our
business.

CONSOLIDATIONS, MERGERS AND PURCHASES OF ASSETS

     The indenture also provides that we will not consolidate with or merge into
any other corporation, or sell all or substantially all of our assets to any
other person unless:

     - the continuing corporation or the purchaser of assets, as the case may
       be, will be an entity organized and existing under the laws of the United
       States, any state or the District of Columbia, and the entity will
       expressly assume the payment of the principal of and interest on all the
       securities issued under the indenture and the performance and observance
       of all of our covenants and conditions under the indenture by executing a
       supplemental indenture satisfactory to the trustee;

     - the entity will not, immediately after the consolidation, merger or sale
       of assets, be in default in the performance of any covenant or condition
       of the indenture; and

     - after giving effect to the transaction, no event which, after notice or
       lapse of time, would become a default under the indenture will have
       occurred or be continuing.

     The indenture further provides that our successor will be substituted for
us, after which all of our obligations under the indenture and our obligations
with respect to the senior debentures will terminate.

     Because we will be the surviving corporation in the proposed merger with
Interstate Power Company, the above provision will not apply to that merger.

DEFAULTS AND REMEDIES

     Each of the following will be an event of default with respect to the
senior debentures:

     - default for 60 days in the payment of any interest on the senior
       debentures;

     - default for 10 days in the payment of principal of the senior debentures;

     - default in the performance of any of our other agreements in the
       indenture and the default continues for 60 days after we receive notice
       of the default from the trustee or the holders of at least 33% in
       principal amount of the senior debentures; or

     - specified events in bankruptcy, insolvency or reorganization.

     If an event of default with respect to the senior debentures occurs and is
continuing, then either the trustee or the holders of at least 33% in principal
amount of the senior debentures can declare the principal of, and all unpaid
interest on, the senior debentures to be immediately due and payable.

     The trustee can require that it be indemnified before it enforces the
indenture or the senior debentures. Subject to some limitations, holders of a
majority in principal amount of the senior debentures can direct the trustee in
its exercise of any trust or power. The trustee does not have to give you notice
of any continuing default, except a default in payment of principal or interest,
if it in good faith determines that withholding notice is in your interest. We
are required to give the trustee a brief certificate certifying as to our
compliance with all conditions and covenants under the indenture at least once a
year.
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   11

     The indenture does not have a cross-default provision. That means that if
we default on any other debt, that default will not constitute an event of
default under the indenture. A default on other series of securities under the
indenture will not necessarily result in an event of default with respect to the
senior debentures offered hereby.

AMENDMENTS AND WAIVERS

     Waivers. The holders of not less than a majority in principal amount of the
senior debentures can waive any existing default and its consequences under the
senior debentures or the indenture. However, holders cannot waive a default in
the payment of the principal of, or interest on, the senior debentures or a
default in respect of a provision we describe in the paragraph that follows;
these defaults cannot be modified or amended without the consent of each holder
of the senior debentures.

     Amendments with Consent. With the consent of the holders of not less than a
majority in aggregate principal amount of the senior debentures, we and the
trustee can enter into supplemental indentures to amend or modify the indenture
or the senior debentures, if those amendments do not affect any other series of
securities we issued under the indenture. However, we cannot make modifications
or amendments without the consent of all of the holders of the senior debentures
if those amendments or modifications would:

     - change the stated maturity, reduce the principal amount of, or reduce the
       rate of interest on, the senior debentures;

     - change the coin or currency in which we must pay principal of, and
       interest on, the senior debentures;

     - impair the right to institute suit for the enforcement of any payment of
       principal of, or interest on, the senior debentures after the due date of
       the payment;

     - reduce the amount of senior debentures whose holders must consent to an
       amendment or waiver of the provisions of the indenture or the senior
       debentures; or

     - make certain modifications to any of the provisions we describe in this
       paragraph and in the paragraph immediately above.

     We cannot enter into supplemental indentures to amend or modify the
indenture in ways that affect other series of securities we issued under the
indenture without the consent of the holders of not less than a majority in
aggregate principal amount of all securities issued under the indenture that
will be affected by the amendment, voting together as one class. Furthermore, if
any amendment or modification would have any of the effects described in the
previous paragraph, and would affect more than one series of securities issued
under the indenture, then we cannot make the amendment or modification without
the consent of all of the holders of the securities issued under the indenture
that would be affected by them.

     Amendments without Consent. We and the trustee can also enter into
supplemental indentures to amend or modify the indenture or the senior
debentures without the consent of any holders of the senior debentures. We can
only do so if those amendments or modifications would have certain purposes,
including:

     - showing that another person has succeeded us and assumed our obligations
       under the covenants of the indenture and the senior debentures;

     - adding to our covenants under the indenture for the benefit of all
       holders of securities under the indenture or surrender any right or power
       we have under the indenture;

     - adding to, changing or eliminating any of the provisions of the indenture
       in respect of the senior debentures, but only if the change does not
       adversely affect the rights of the holders of the securities under the
       indenture in any material respect;

     - establishing the form or terms of securities of any series;

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     - evidencing the appointment of a successor trustee or a change in any of
       the provisions of the indenture to facilitate administration by more than
       one trustee; or

     - making clarifying changes to ambiguous, incorrect or inconsistent
       language in the indenture or the senior debentures that do not adversely
       affect the rights of the holders of the securities under the indenture in
       any material respect.

DEFEASANCE

     The indenture provides that we can at any time terminate almost all of our
obligations with respect to the senior debentures and the indenture. We cannot,
however, terminate some obligations, including our obligations to register the
transfer or exchange of the senior debentures, replace mutilated, destroyed,
lost or stolen senior debentures, to maintain agencies in respect of the senior
debentures and hold moneys for payment in trust.

     If we desire to exercise our option to satisfy and discharge our
obligations under the indenture (a defeasance), then we must deposit in trust
with the trustee money or U.S. government obligations sufficient to pay the
outstanding principal amount of the senior debentures as well as the interest on
the senior debentures to maturity. We must also comply with some other
conditions. In particular, we must obtain:

     - an opinion of tax counsel that the defeasance will not result in
       recognition of any gain or loss to holders of the senior debentures for
       federal income tax purposes;

     - an opinion of counsel that any U.S. government obligations that we
       deposit in trust meet the requirements of U.S. government obligations set
       forth in the indenture; and

     - an opinion of a nationally recognized independent public accountant to
       the effect that we have deposited with the trustee money or U.S.
       government obligations sufficient to pay the outstanding principal amount
       of the senior debentures as well as the interest on the senior debentures
       to maturity.

When we refer to "U.S. government obligations," we refer to direct obligations
of the United States of America which have the full faith and credit of the
United States of America pledged for payment and which are not callable at the
issuer's option, or certificates representing an ownership interest in those
obligations.

THE TRUSTEE

     Bank One Trust Company, National Association will act as trustee,
registrar, transfer agent and paying agent for the senior debentures. We can
remove the trustee with or without cause so long as no event which is, or after
notice or lapse of time would become, an event of default shall have occurred
and be continuing.

     We and certain of our affiliates maintain banking and other business
relationships in the ordinary course of business with the trustee and its
affiliates. In addition, the trustee and certain of its affiliates may serve as
trustee for other securities issued by us or by our affiliates.

     To the extent provided in the indenture, the trustee will have a prior
claim on amounts held by it under the indenture for the payment of its
compensation and expenses and for the repayment of advances made by it to effect
performance of some covenants in the indenture.

BOOK-ENTRY DELIVERY AND SETTLEMENT

     We will issue the senior debentures in the form of one or more permanent
global securities in definitive, fully registered form. The global securities
will be deposited with or on behalf of The Depository Trust Company, referred to
as DTC, and registered in the name of Cede & Co., as nominee of DTC, or

                                        11
   13

will remain in the custody of the trustee in accordance with the FAST Balance
Certificate Agreement between DTC and the trustee.

     DTC has advised us that:

     - DTC is a limited-purpose trust company organized under the New York
       Banking Law, a "banking organization" within the meaning of the New York
       Banking Law, a member of the Federal Reserve System, a "clearing
       corporation" within the meaning of the New York Uniform Commercial Code
       and a "clearing agency" registered under Section 17A of the Securities
       Exchange Act of 1934;

     - DTC holds securities that its direct participants deposit with DTC and
       facilitates the settlement among direct participants of securities
       transactions, such as transfers and pledges, in deposited securities
       through electronic computerized book-entry changes in direct
       participants' accounts, thereby eliminating the need for physical
       movement of securities certificates;

     - direct participants include securities brokers and dealers, trust
       companies, clearing corporations and other organizations;

     - DTC is owned by a number of its direct participants and by the New York
       Stock Exchange, Inc., the American Stock Exchange LLC and the National
       Association of Securities Dealers, Inc.;

     - access to the DTC system is also available to indirect participants such
       as securities brokers and dealers, banks and trust companies that clear
       through or maintain a custodial relationship with a direct participant,
       either directly or indirectly; and

     - the rules applicable to DTC and its direct and indirect participants are
       on file with the SEC.

     We have provided the following descriptions of the operations and
procedures of DTC solely as a matter of convenience. These operations and
procedures are solely within the control of DTC and are subject to change by
them from time to time. Neither we, the underwriters nor the trustee take any
responsibility for these operations or procedures, and you are urged to contact
DTC or its participants directly to discuss these matters.

     We expect that under procedures established by DTC:

     - upon deposit of the global securities with DTC or its custodian, DTC will
       credit on its internal system the accounts of direct participants
       designated by the underwriters with portions of the principal amounts of
       the global securities; and

     - ownership of the senior debentures will be shown on, and the transfer of
       ownership of the senior debentures will be effected only through, records
       maintained by DTC or its nominee, with respect to interests of direct
       participants, and the records of direct and indirect participants, with
       respect to interests of persons other than participants.

     The laws of some jurisdictions require that purchasers of securities take
physical delivery of those securities in the form of a certificate. For that
reason, it may not be possible to transfer interests in a global security to
those persons. In addition, because DTC can act only on behalf of its
participants, who in turn act on behalf of persons who hold interests through
participants, the ability of a person having an interest in a global security to
pledge or transfer that interest to persons or entities that do not participate
in DTC's system, or otherwise to take actions in respect of that interest, may
be affected by the lack of a physical definitive security in respect of that
interest.

     So long as DTC or its nominee is the registered owner of a global security,
DTC or that nominee will be considered the sole owner or holder of the senior
debentures represented by that global security for all purposes under the
indenture and under the senior debentures. Except as described below, owners of
beneficial interests in a global security will not be entitled to have senior
debentures represented by that global security registered in their names, will
not receive or be entitled to receive the senior debentures in the form of a
physical certificate and will not be considered the owners or holders of the
senior debentures under the indenture or under the senior debentures, and may
not be entitled to give the trustee directions,

                                        12
   14

instructions or approvals. For that reason, each holder owning a beneficial
interest in a global security must rely on DTC's procedures and, if that holder
is not a direct or indirect participant in DTC, on the procedures of the DTC
participant through which that holder owns its interest, to exercise any rights
of a holder of senior debentures under the indenture or the global security.

     Neither we nor the trustee will have any responsibility or liability for
any aspect of DTC's records relating to the senior debentures or relating to
payments made by DTC on account of the senior debentures, or any responsibility
to maintain, supervise or review any of DTC's records relating to the senior
debentures.

     We will make payments on the senior debentures represented by the global
securities to DTC or its nominee, as the registered owner of the senior
debentures. We expect that when DTC or its nominee receives any payment on the
senior debentures represented by a global security, DTC will credit
participants' accounts with payments in amounts proportionate to their
beneficial interests in the global security as shown in DTC's records. We also
expect that payments by DTC's participants to owners of beneficial interests in
the global security held through those participants will be governed by standing
instructions and customary practice as is now the case with securities held for
the accounts of customers registered in the names of nominees for such
customers. DTC's participants will be responsible for those payments.

     Payments on the senior debentures represented by the global securities will
be made in immediately available funds. Transfers between participants in DTC
will be made in accordance with DTC's rules and will be settled in immediately
available funds.

CERTIFICATED SENIOR DEBENTURES

     We will issue certificated senior debentures to each person that DTC
identifies as the beneficial owner of senior debentures represented by the
global securities upon surrender by DTC of the global securities only if:

     - DTC notifies us that it is no longer willing or able to act as a
       depository for the global securities, and we have not appointed a
       successor depository within 90 days of that notice;

     - an event of default with respect to the senior debentures has occurred
       and is continuing; or

     - we decide not to have the senior debentures represented by a global
       security.

     Neither we nor the trustee will be liable for any delay by DTC, its nominee
or any direct or indirect participant in identifying the beneficial owners of
the related senior debentures. We and the trustee may conclusively rely on, and
will be protected in relying on, instructions from DTC or its nominee, including
instructions about the registration and delivery, and the respective principal
amounts, of the senior debentures to be issued.

                                        13
   15

                                  UNDERWRITING

     We have entered into an underwriting agreement with the underwriters named
below, for whom Legg Mason Wood Walker, Incorporated is acting as
representative. Under the terms and subject to the conditions of the
underwriting agreement, we have agreed to sell to each of the underwriters, and
each of the underwriters has agreed to purchase, severally and not jointly, the
principal amount of senior debentures shown opposite its name below:



                                                                 PRINCIPAL
                        UNDERWRITERS                               AMOUNT
                        ------------                             ---------
                                                             
Legg Mason Wood Walker, Incorporated........................    $ 60,000,000
Merrill Lynch, Pierce, Fenner & Smith
             Incorporated...................................      60,000,000
Robert W. Baird & Co. Incorporated..........................      26,800,000
Utendahl Capital Partners, L.P. ............................      26,600,000
Wachovia Securities, Inc. ..................................      26,600,000
                                                                ------------
     Total..................................................    $200,000,000
                                                                ============


     Under the terms of the underwriting agreement, the underwriters must
purchase all of the senior debentures if they purchase any of them. The
underwriters will pay us the public offering price less the underwriting
discount specified on the cover of this prospectus. We estimate that we will
incur approximately $265,000 of expenses, not including the underwriting
discount, in connection with the offering of the senior debentures.

     The underwriters plan to offer the senior debentures directly to retail
purchasers at the public offering price and to some securities dealers at the
public offering price less a selling concession of 0.40% of the principal amount
of the senior debentures. The underwriters may allow, and these selected dealers
may reallow, a concession that will not exceed 0.25% of the principal amount of
the senior debentures on sales to other brokers and dealers. After the initial
offering of the senior debentures to the public, the underwriters may change the
public offering price and other selling terms.

     We have agreed to indemnify the underwriters against some liabilities,
including liabilities under the Securities Act of 1933.

     The underwriters have advised us that one or more of them currently intend
to make a market in the senior debentures. However, they are not obligated to do
so and may discontinue making a market at any time without notice. We do not
intend to list the senior debentures on any securities exchange or for quotation
through any national quotation system. Accordingly, we cannot assure you that
there will be adequate liquidity or an adequate trading market for the senior
debentures.

     In connection with the offering of the senior debentures, the underwriters
may engage in transactions that stabilize the price of the senior debentures.
These transactions may consist of bids or purchases for the purpose of pegging,
fixing or maintaining the price of the senior debentures. In general, the
purchase of a security for the purpose of stabilization could cause the price of
that security to be higher than it might otherwise be in the absence of those
purchases. Neither we nor the underwriters make any representation or prediction
as to the effect that transactions of the type described above may have on the
price of the senior debentures. In addition, if the underwriters do engage in
these types of transactions, they may discontinue them at any time without
notice.

     It is expected that delivery of the senior debentures will be made against
payment for the senior debentures on or about March 12, 2001, which is the
fourth business day following the date of this prospectus. We refer to this
settlement cycle as T+4. Purchasers of the senior debentures should note that
trading of the senior debentures on the date of this prospectus may be affected
by the T+4 settlement.

                                        14
   16

                      WHERE YOU CAN FIND MORE INFORMATION

     We file annual, quarterly and current reports and proxy statements and
other information with the SEC. You may read and copy any document which we file
at the SEC's public reference rooms at 450 Fifth Street, N.W., Washington, D.C.,
and at regional SEC offices in Chicago, Illinois and New York, New York. You can
also find our public filings with the SEC on the internet at a web site
maintained by the SEC located at http://www.sec.gov.

     We are "incorporating by reference" specified documents that we file with
the SEC, which contain important business and financial information not included
in or delivered with this prospectus. "Incorporating by reference" means:

     - incorporated documents are considered part of this prospectus;

     - we are disclosing important information to you by referring you to those
       documents; and

     - information we file with the SEC will automatically update and supersede
       information contained in this prospectus.

     We incorporate by reference the documents listed below and any future
filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the
Securities Exchange Act of 1934 after the date of this prospectus and before the
completion of the offering:

     - our Annual Report on Form 10-K for the year ended December 31, 1999;

     - our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2000,
       June 30, 2000 and September 30, 2000;

     - our Proxy Statement/Prospectus included in our Registration Statement on
       Form S-4/A filed with the SEC on February 12, 2001, which became
       effective on February 13, 2001; and
     - our Current Report on Form 8-K dated February 20, 2001 as amended by our
       Current Report on Form 8-K/A dated March 1, 2001.

     YOU MAY REQUEST A COPY OF ANY OF THESE FILINGS (INCLUDING EXHIBITS), AT NO
COST, BY WRITING TO EDWARD M. GLEASON, VICE PRESIDENT - TREASURER AND CORPORATE
SECRETARY, IES UTILITIES INC., 222 WEST WASHINGTON AVENUE, MADISON, WISCONSIN
53703, OR BY CALLING MR. GLEASON AT (608) 252-3311.

                           FORWARD-LOOKING STATEMENTS

     This prospectus (including the information we incorporate by reference)
contains forward-looking statements that are not of historical fact and are
statements intended to qualify for the safe harbors from liability established
by the Private Securities Litigation Reform Act of 1995. From time to time, we
may make other forward-looking statements within the meaning of the federal
securities laws that involve judgments, assumptions and other uncertainties
beyond our control. These forward-looking statements may include, among others,
statements concerning revenue and cost trends, cost recovery, cost reduction
strategies and anticipated outcomes, pricing strategies, changes in the utility
industry, planned capital expenditures, financing needs and availability,
statements of expectations, beliefs, future plans and strategies, anticipated
events or trends and similar comments concerning matters that are not historical
facts. You are cautioned that these statements are not a guarantee of future
performance and that these forward-looking statements are subject to risks and
uncertainties that could cause actual results to differ materially from those
expressed in, or implied by, these statements. Some, but not all, of the risks
and uncertainties include:

     - weather effects on sales and revenues;

     - competitive factors;

     - general economic conditions in the relevant service territory;

                                        15
   17

     - federal and state regulatory or government actions, including issues
       associated with the deregulation of the utility industry and the setting
       of rates;

     - unanticipated construction and acquisition expenditures;

     - issues related to stranded costs and their recovery;

     - unanticipated issues related to the supply of purchased electricity and
       price thereof;

     - the operations of our nuclear facility;

     - unanticipated costs associated with certain environmental remediation
       efforts we are undertaking;

     - technological developments;

     - employee workforce factors, including changes in key executives,
       collective bargaining agreements or work stoppages; and

     - changes in the rate of inflation.

                                 LEGAL OPINIONS

     Kent M. Ragsdale, our Managing Attorney, and Foley & Lardner, Milwaukee,
Wisconsin, will issue opinions with respect to the legality of the senior
debentures and certain other legal matters with respect to the senior
debentures. Pillsbury Winthrop LLP, New York, New York, will issue an opinion to
the underwriters about certain legal matters with respect to the senior
debentures. Foley & Lardner and Pillsbury Winthrop LLP will rely on the opinion
of Mr. Ragsdale for all matters pertaining to Iowa corporate law.

                                    EXPERTS

     Our financial statements and schedules at December 31, 1999 and 1998 and
for each of the three years in the period ending December 31, 1999 and the
financial statements and schedules of Interstate Power Company at December 31,
1999 and 1998 and for each of the two years in the period ending December 31,
1999 incorporated by reference in this prospectus and elsewhere in the
registration statement have been audited by Arthur Andersen LLP, independent
public accountants, as indicated in their reports with respect thereto, and are
included herein in reliance upon the authority of said firm as experts in giving
said reports. The financial statements and schedules of Interstate Power Company
for the year ending December 31, 1997 incorporated by reference in this
prospectus and elsewhere in this registration statement have been audited by
Deloitte & Touche LLP, independent auditors, as stated in their report, which is
incorporated herein by reference, and have been so incorporated in reliance upon
the report of such firm given upon their authority as experts in accounting and
auditing.

                                        16
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- ------------------------------------------------------
- ------------------------------------------------------

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED OR INCORPORATED BY REFERENCE
IN THIS PROSPECTUS OR TO WHICH WE HAVE REFERRED YOU. WE HAVE NOT AUTHORIZED ANY
OTHER PERSON TO PROVIDE YOU WITH DIFFERENT INFORMATION. THIS PROSPECTUS MAY ONLY
BE USED WHERE IT IS LEGAL TO SELL THESE SECURITIES. YOU SHOULD ASSUME THAT THE
INFORMATION CONTAINED OR INCORPORATED BY REFERENCE IN THIS PROSPECTUS IS
ACCURATE AS OF THE DATE ON THE FRONT COVER OF THIS PROSPECTUS ONLY. OUR
BUSINESS, FINANCIAL CONDITION, RESULTS OF OPERATIONS AND PROSPECTS MAY HAVE
CHANGED SINCE THAT DATE.

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

                               TABLE OF CONTENTS



                                          PAGE
                                          ----
                                       
IES Utilities Inc. ...................      1
Use of Proceeds.......................      4
Capitalization........................      4
Summary Financial Information.........      5
Ratios of Earnings to Fixed Charges...      6
Description of the Senior
  Debentures..........................      7
Underwriting..........................     14
Where You Can Find More Information...     15
Forward-Looking Statements............     15
Legal Opinions........................     16
Experts...............................     16


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

                                  $200,000,000

                                 [ALLIANT LOGO]

                               IES UTILITIES INC.

                             6 3/4% SERIES B SENIOR
                              DEBENTURES DUE 2011
                              --------------------

                                   PROSPECTUS
                              --------------------
                                 MARCH 6, 2001

                             LEGG MASON WOOD WALKER
                                  INCORPORATED

                              MERRILL LYNCH & CO.
                             ROBERT W. BAIRD & CO.
                        UTENDAHL CAPITAL PARTNERS, L.P.
                           WACHOVIA SECURITIES, INC.

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