(As filed March 31, 2004)
                                                               File No. 70-10207

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

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

                                   FORM U-1/A

                                 Amendment No. 1
                                       to
                           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





     The Application/Declaration filed in this proceeding on March 5, 2004 is
hereby amended and restated in its entirety to read as follows:

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 966,000 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's principal direct subsidiaries 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 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 December 31, 2003, Alliant Energy's consolidated capitalization
was as follows:



---------------------------     ----------------     --------
                                                 
Common Equity                    $2,371,314,000        47.5%
---------------------------     ----------------     --------
Preferred Equity                  $ 243,803,000         4.9%
---------------------------     ----------------     --------
Long-term Debt*                  $2,178,398,000        43.6%
---------------------------     ----------------     --------
Short-term Debt**                 $ 198,276,000         4.0%
---------------------------     ----------------     --------
                     Total       $4,991,791,000       100.0%
---------------------------     ----------------     --------

     *    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").


                                      -2-



          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 March 31, 2004, 111,321,380 shares were issued and outstanding. In
addition, as of March 31, 2004, 1,734,781 shares of common stock were reserved
for issuance under Alliant Energy's Shareowner Direct Plan, 3,730,919 shares
were reserved for issuance under its Long-Term Equity Incentive Plan, 3,923,164
shares were reserved for issuance under its 2002 Equity Incentive Plan, 153,289
shares were reserved for issuance under its 401(k) Plan, and 60,431,767 shares
were reserved for issuance under its Rights Agreement./1/ As a result, there are
now only 18,704,700 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/

          1.3  The 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


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

/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-



notice of annual meeting, proxy statement, and proxy card are filed herewith as
Exhibit 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 December 31, 2003, Alliant Energy's "aggregate investment," as
defined in Rule 53(a)(1), in EWGs and FUCOs was approximately $517.5 million, or
approximately 66.0% of Alliant Energy's average "consolidated retained
earnings," also as defined in Rule 53(a)(1), for the four quarters ended
December 31, 2003 ($784.6 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


                                      -4-



Alliant Energy's FUCO investments in Australia in April 2003, the sale of its
affordable housing and SmartEnergy businesses in mid-2003, and the sale of
approximately 94% of its oil and gas exploration and production business in
November 2003) and the application of the proceeds to retire more than $800
million of 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 million) were used to make capital
contributions to IP&L and WP&L; and implementation of other cost control
measures./4/

          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 years 2001 and 2002, Alliant Energy's share of
losses totaled approximately $25.3 million and $26.7 million, respectively.
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. In fiscal year 2003,
Alliant Energy's share of income was approximately $3.8 million (not including
gain from sale of Australian FUCO investments).

          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
specified in Rule 53(b) exists./5/


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

/4/  As noted in Item 1 above, at December 31, 2003, Alliant Energy's
consolidated capitalization consisted of 47.5% common equity, 4.9% preferred
stock, 43.6% long-term debt (including variable rate demand bonds classified as
current), and 4.0% 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/  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.


                                      -5-



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 (previously filed).

               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.

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


                                      -6-



               G    Proposed Form of Federal Register Notice (previously filed).


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

               1.1  Balance Sheet of Alliant Energy and consolidated
                    subsidiaries, as of December 31, 2003 (incorporated by
                    reference to the Annual Report on Form 10-K of Alliant
                    Energy for the year ended December 31, 2003) (File
                    No. 1-9894).

               1.2  Statement of Income of Alliant Energy and consolidated
                    subsidiaries for the twelve months ended December 31, 2003
                    (incorporated by reference to the Annual Report on Form 10-K
                    of Alliant Energy for the year ended December 31, 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.

                                    SIGNATURE

          Pursuant to the requirements of the Public Utility Holding Company Act
of 1935, as amended, the undersigned company has duly caused this amended
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 31, 2004