(As filed March 5, 2003)

                                                               File No. 70-[___]


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

                                    FORM U-1

                           APPLICATION OR DECLARATION
                                    UNDER THE
                   PUBLIC UTILITY HOLDING COMPANY ACT OF 1935

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

                           ALLIANT ENERGY CORPORATION
                              4902 N. Biltmore Lane
                            Madison, Wisconsin 53718

                     (Name of company filing this statement
                   and address of principal executive offices)

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

                           ALLIANT ENERGY CORPORATION

                 (Name of top registered holding company parent)

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

                         F. J. Buri, Corporate Secretary
                           Alliant Energy Corporation
                              4902 N. Biltmore Lane
                            Madison, Wisconsin 53718

                     (Name and address of agent for service)

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

      The Commission is requested to send copies of all notices, orders and
      communications in connection with this Application or Declaration to:

Barbara J. Swan, Executive Vice President            William T. Baker, Jr., Esq.
           and General Counsel                         Thelen Reid & Priest LLP
       Alliant Energy Corporation                          875 Third Avenue
          4902 N. Biltmore Lane                        New York, New York 10022
        Madison, Wisconsin 53718





ITEM 1.  DESCRIPTION OF PROPOSED TRANSACTION.
         -----------------------------------

     1.1 Introduction. Alliant Energy Corporation ("Alliant Energy") is a
registered holding company under the Public Utility Holding Company Act of 1935,
as amended (the "Act"). Its principal public-utility subsidiaries are Interstate
Power and Light Company ("IP&L"), Wisconsin Power and Light Company ("WP&L"),
and South Beloit Water, Gas and Electric Company (collectively, the "Utility
Subsidiaries"). Together, the Utility Subsidiaries provide public-utility
service to approximately 965,000 electric and 408,000 retail gas customers in
parts of Wisconsin, Iowa, Minnesota, and Illinois. Alliant Energy also
indirectly holds 25% of the common stock of ATC Management, Inc. and a 25%
membership interest in American Transmission Company, LLC, which were formed to
acquire, own and manage the Wisconsin transmission assets of Alliant Energy and
certain other Wisconsin electric utility companies.

     Alliant Energy's direct non-utility subsidiaries include Alliant Energy
Corporate Services, Inc., a subsidiary service company, and Alliant Energy
Resources, Inc. ("AER"), which serves as the holding company for substantially
all of Alliant Energy's non-utility investments and subsidiaries. AER owns five
principal direct subsidiaries that are engaged, directly and indirectly through
other subsidiaries, in (i) providing environmental consulting and engineering
services, (ii) energy-related businesses, including, among others, the brokering
and marketing of electricity and natural gas, gas supply and fuel management
services, steam production and sale, and energy-management services, (iii)
owning and/or operating "exempt wholesale generators" ("EWGs") and "foreign
utility companies" ("FUCOs"), as defined in Sections 32 and 33, respectively, of
the Act, (iv) rail transportation, and (v) management of investments in
telecommunications.

     As of September 30, 2003, Alliant Energy's consolidated capitalization was
as follows:



--------------------------------------------------------------------------------
                                                                 
Common Equity                    $2,314,507,000                         43.9%
--------------------------------------------------------------------------------
Preferred Equity                 $  243,803,000                          4.6%
--------------------------------------------------------------------------------
Long-term Debt*                  $2,350,943,000                         44.6%
--------------------------------------------------------------------------------
Short-term Debt**                $  363,495,000                          6.9%
--------------------------------------------------------------------------------
                    Total        $5,272,748,000                        100.00%
--------------------------------------------------------------------------------

     *  Includes variable rate demand bonds classified as current.
     ** Includes current portion of Long-term Debt.



     1.2 Summary of Requested Approvals. In this Application/Declaration,
Alliant Energy is seeking authorization to amend its Restated Articles of
Incorporation, as amended ("Restated Articles"), to increase the number of
authorized shares of common stock that it may issue from 200 million to 240
million, and to solicit shareholder consents in connection with such amendment
for use at its annual shareholders' meeting ("Annual Meeting") scheduled for May
21, 2004 ("Proxy Solicitation").


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     Alliant Energy is authorized under its Restated Articles (Exhibit A-1
hereto) to issue 200,000,000 shares of common stock, $0.01 par value per share.
As of December 31, 2003, 110,962,910 shares were issued and outstanding. In
addition, as of December 31, 2003, 1,914,047 shares of common stock were
reserved for issuance under Alliant Energy's Shareowner Direct Plan, 2,433,182
shares were reserved for issuance under its Long-Term Equity Incentive Plan,
3,800,000 shares were reserved for issuance under its 2002 Equity Incentive
Plan, 220,440 shares were reserved for issuance under its 401(k) Plan, and
59,665,290 shares were reserved for issuance under its Rights Agreement./1/ As a
result, there are now only 21,004,131 authorized shares of Alliant Energy common
stock that are not reserved and that may be issued for any future business
purposes. Accordingly, Alliant Energy's Board of Directors has approved for
submission to its shareowners at its 2004 Annual Meeting an amendment to the
Restated Articles to increase the number of authorized shares of common stock
from 200,000,000 to 240,000,000. The form of Articles of Amendment to the
Restated Articles is filed herewith as Exhibit A-2.

     Alliant Energy anticipates that it will require in the future a greater
number of authorized shares of common stock than is currently available under
its Restated Articles to issue new equity to fund its capital expenditure
program, including the recently announced domestic regulated generation
build-out program./2/ However, Alliant Energy is not requesting any new or
additional financing authority as part of this Application/Declaration./3/

     1.3The Proxy Solicitation. Alliant Energy requests authorization to solicit
shareholder consents in connection with the proposed amendment to its Restated
Articles at its Annual Meeting scheduled for May 21, 2004. The forms of notice
of annual meeting, proxy statement, and proxy card are filed herewith as Exhibit

----------
1    The Commission authorized Alliant Energy (then named Interstate Energy
     Company) to implement a Rights Agreement by order dated January 15, 1999 in
     File No. 70-9401. See Interstate Energy Company, Holding Co. Act Release
     No. 26965. Under the Right Agreement, following a triggering event, the
     outstanding rights (subject to certain limitations) could be exercised by
     the holders thereof to purchase common stock of Alliant Energy having a
     value equal to two times the Purchase Price (as defined under the Rights
     Agreement).

2    In December 2003, Alliant Energy announced that it intends to add a
     diversified portfolio of approximately 1,600 megawatts nameplate generation
     in its service area between 2004 and 2010 at an estimated capital cost of
     $650 million.

3    By order dated October 3, 2001 in File No. 70-9891 (Holding Co. Act Release
     No. 27448), as modified by supplemental order dated December 17, 2002
     (Holding Co. Act Release No. 27620), Alliant Energy is currently authorized
     to issue and sell equity and unsecured long-term debt securities from time
     to time through December 31, 2004 in an aggregate amount at any time
     outstanding not to exceed $1.5 billion, subject to various limitations and
     restrictions, and up to 8 million shares of common stock pursuant to its
     shareowner direct plan and pursuant to incentive compensation and
     stock-purchase plans maintained for its and its subsidiaries' officers and
     employees and non-management directors, as they may be amended or extended,
     and similar plans or plan funding arrangements hereafter adopted. Alliant
     Energy intends to file a separate application/declaration later in 2004 to
     restate and extend its financing authorization under the October 3, 2001
     order, as previously modified.


                                      -3-



B-1. To approve the proposed amendment to the Restated Articles, the number of
votes cast in favor of the proposed amendment must exceed the number of votes
cast against it at the Annual Meeting.

ITEM 2.  FEES, COMMISSIONS AND EXPENSES.
         ------------------------------

     The total fees, commissions and expenses paid or incurred or to be paid or
incurred in connection with the proposed transactions are estimated as follows:

          Attorneys fees and expenses                $15,000

          Other expenses of Proxy Solicitation       $ 6,000
                                                     -------

               Total                                 $21,000


ITEM 3.  APPLICABLE STATUTORY PROVISIONS.
         -------------------------------

     3.1 General. Sections 6(a) and 7 of the Act are applicable to the proposed
amendment to the Restated Articles, and Section 12(e) of the Act and Rules 62
and 65 thereunder are applicable to the Proxy Solicitation.

     3.2 Compliance with Rules 53 and 54. The proposed transaction is also
subject to Section 32(h) of the Act and Rule 54 thereunder. Rule 54 provides
that, in determining whether to approve any transaction that does not relate to
an EWG or FUCO, as defined in Sections 32 and 33, respectively, the Commission
shall not consider the effect of the capitalization or earnings of any
subsidiary which is an EWG or FUCO upon the registered holding company system if
paragraphs (a), (b) and (c) of Rule 53 are satisfied.

     Alliant Energy currently does not meet all of the conditions of Rule 53(a).
As of September 30, 2003, Alliant Energy's "aggregate investment," as defined in
Rule 53(a)(1), in EWGs and FUCOs was approximately $465.1 million, or
approximately 60.9% of Alliant Energy's average "consolidated retained
earnings," also as defined in Rule 53(a)(1), for the four quarters ended
September 30, 2003 ($764.0 million). Although this exceeds the 50% "safe harbor"
limitation contained in Rule 53(a), the Commission has authorized Alliant Energy
under the October 3, 2001 order, note 3 above, to increase its "aggregate
investment" in EWGs and FUCOs to an amount equal to 100% of Alliant Energy's
average "consolidated retained earnings."

     Even if the Commission takes into account the capitalization of and
earnings from EWGs and FUCOs in which Alliant Energy has an interest, there
would be no basis for withholding approval of the proposed transaction. With
regard to capitalization, Alliant Energy has experienced an increase in
consolidated common stock equity since September 30, 2001, the end of the
quarterly period immediately preceding the issuance of the October 3, 2001
order, due in part to the sale of certain non-regulated businesses (including
Alliant Energy's FUCO investments in Australia, which was completed in late


                                      -4-



April 2003, and the sale of Alliant Energy's affordable housing business, which
was completed in mid-2003) and the application of the proceeds to retire debt;
halving the targeted dividend on common stock from $2.00 per share to $1.00 per
share; reducing anticipated capital expenditures in 2002 and 2003 (including no
new investments in Brazil through 2003); completion of a public offering of
17,250,000 shares of common stock in July 2003, the net proceeds of which
(approximately $318.4 million) were used to make capital contributions to IP&L
and WP&L ; and implementation of other cost control measures./4/ As a result of
the above completed and other completed and proposed asset sales, Alliant Energy
expects to achieve aggregate debt reduction in excess of $800 million with a
significant majority, if not all, expected to occur by the end of 2004.

     Finally, the proposed transaction will have no impact on Alliant Energy's
consolidated capitalization.

     Since the issuance of the October 3, 2001 order, Alliant Energy has
experienced a modest increase in its level of losses from its portfolio of
FUCOs. As described in the Application/Declaration in File No. 70-9891, Alliant
Energy's share of losses associated with its portfolio of FUCOs in fiscal year
2000 (the last fiscal year prior to issuance of the October 3, 2001 order)
totaled approximately $17.7 million, after interest expense, taxes and currency
transaction losses. In fiscal year 2001, Alliant Energy's share of losses
totaled approximately $25.3 million./5/ Alliant Energy's losses on its Brazil
investments were unexpectedly large in 2002, resulting primarily from the impact
of a decline in currency translation rates, as well as from charges related to
recovery of the impacts of electricity rationing in Brazil and other prior
costs. Since then, energy demand has increased and several rate increases have
been approved.

     Alliant Energy satisfies all of the other conditions of paragraphs (a) and
(b) of Rule 53. With reference to Rule 53(a)(2), Alliant Energy maintains books
and records in conformity with, and otherwise adheres to, the requirements
thereof. With reference to Rule 53(a)(3), no more than 2% of the employees of
Alliant Energy's domestic public utility companies render services, at any one
time, directly or indirectly, to EWGs or FUCOs in which Alliant Energy directly
or indirectly holds an interest. With reference to Rule 53(a)(4), Alliant Energy
will continue to provide a copy of each application and certificate relating to
EWGs and FUCOs and relevant portions of its Form U5S to each regulator referred
to therein, and will otherwise comply with the requirements thereof concerning
the furnishing of information. In addition, none of the adverse conditions

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4    As noted in Item 1 above, at September 30, 2003, Alliant Energy's
     consolidated capitalization consisted of 43.9% common equity, 4.6%
     preferred stock, 44.6% long-term debt (including variable rate demand bonds
     classified as current), and 6.9% short-term debt (including current
     maturities of long-term debt), versus 36.3% common equity, 2.6% preferred
     stock, 51.2% long-term debt (including variable rate demand bonds
     classified as current), and 9.9% short-term debt (including current
     maturities of long-term debt) at September 30, 2001 (the end of the quarter
     immediately preceding the October 3, 2001 order).

5    Source: Alliant Energy's Annual Report on Form U5S for the year ended
     December 31, 2001 (Alliant Energy's share only).


                                      -5-



specified in Rule 53(b) exists./6/

ITEM 4.  REGULATORY APPROVALS.
         --------------------

     No state commission, and no federal commission, other than the Commission,
has jurisdiction over the proposed transactions.

ITEM 5.  PROCEDURE.
         ---------

     The Commission is requested to publish a notice under Rule 23 with respect
to the filing of this Application/Declaration as soon as practicable after the
proxy statement with respect to the Proxy Solicitation has been declared
effective under the Securities Exchange Act of 1934, as amended, and that such
notice include an order authorizing commencement of the Proxy Solicitation. The
Applicant requests that the Commission's order approving the proposed
transaction be issued as soon as the rules allow, and that there should not be a
30-day waiting period between issuance of the Commission's order and the date on
which the order is to become effective. The Applicant hereby waives a
recommended decision by a hearing officer or any other responsible officer of
the Commission and consents to the assistance of the Division of Investment
Management in the preparation of the Commission's decision and/or order, unless
the Division opposes the matters proposed herein.

ITEM 6.  EXHIBITS AND FINANCIAL STATEMENTS.
         ---------------------------------

         A. EXHIBITS.
            --------

            A-1     Restated Articles of Incorporation of Alliant Energy, as
                    amended (incorporated by reference to Exhibit 3.2 to Alliant
                    Energy's Quarterly Report on Form 10-Q for the quarter ended
                    June 30, 1999, File No. 1-9894).

            A-2     Form of Articles of Amendment to Restated Articles of
                    Incorporation of Alliant Energy.

            B-1     Forms of Notice of Annual Meeting, Proxy Statement and Proxy
                    Card (incorporated by reference to Schedule 14A/Preliminary
                    Proxy Statement, to be filed on March 12, 2004, in File No.
                    1-9894).

             C      None

             D      None.

             E      None.

----------
6    With regard to Rule 53(b)(3), operating losses on Alliant Energy's
     investments in EWGs and FUCOs were less than 5% of consolidated retained
     earnings in 2002.


                                      -6-



             F      Opinion of Counsel (to be filed by amendment).

             G      Proposed Form of Federal Register Notice.


         B. FINANCIAL STATEMENTS.
            --------------------

            1.1     Balance Sheet of Alliant Energy and consolidated
                    subsidiaries, as of December 31, 2002 (incorporated by
                    reference to the Annual Report on Form 10-K of Alliant
                    Energy for the year ended December 31, 2002) (File No.
                    1-9894).

            1.2     Statements of Income of Alliant Energy and consolidated
                    subsidiaries for the twelve months ended December 31, 2002
                    (incorporated by reference to the Annual Report on Form 10-K
                    of Alliant Energy for the period ended December 31, 2002)
                    (File No. 1-9894).

            1.3     Balance Sheet of Alliant Energy and consolidated
                    subsidiaries, as of September 30, 2003 (incorporated by
                    reference to the Quarterly Report on Form 10-Q of Alliant
                    Energy for the period ended September 30, 2003) (File No.
                    1-9894).

            1.4     Statements of Income of Alliant Energy and consolidated
                    subsidiaries for the twelve months ended September 30, 2003
                    (incorporated by reference to the Quarterly Report on Form
                    10-Q of Alliant Energy for the period ended September 30,
                    2003) (File No. 1-9894).


ITEM 7.  INFORMATION AS TO ENVIRONMENTAL EFFECTS.
         ---------------------------------------

     The matters that are the subject of this Application/Declaration do not
involve a "major federal action" nor do they "significantly affect the quality
of the human environment" as those terms are used in section 102(2)(C) of the
National Environmental Policy Act. The transaction that is the subject of this
Application/Declaration will not result in changes in the operation of the
Applicant that will have an impact on the environment. The Applicant is not
aware of any federal agency that has prepared or is preparing an environmental
impact statement with respect to the transactions that are the subject of this
Application/Declaration.


                                      -7-



                                    SIGNATURE

     Pursuant to the requirements of the Public Utility Holding Company Act of
1935, as amended, the undersigned company has duly caused this
Application/Declaration filed herein to be signed on its behalf by the
undersigned thereunto duly authorized.


                                         ALLIANT ENERGY CORPORATION

                                         By: /s/ F. J. Buri
                                                 ----------
                                         Name:   F. J. Buri
                                         Title:  Corporate Secretary


Date:  March 5, 2003


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