8-K

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

_________________

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of
the Securities Exchange Act of 1934

_________________

Date of Report
(Date of earliest
event reported):	May 4, 2005

	Name of Registrant, State of Incorporation, Address of
Commission	Principal Executive	IRS Employer
File Number	Offices and Telephone Number	Identification Number
1-9894	Alliant Energy Corporation	39-1380265
	(a Wisconsin corporation)
	4902 N. Biltmore Lane
	Madison, Wisconsin 53718
	Telephone (608) 458-3311
0-4117-1	Interstate Power and Light Company	42-0331370
	(an Iowa corporation)
	Alliant Energy Tower
	Cedar Rapids, Iowa 52401
	Telephone (319) 786-4411
0-337	Wisconsin Power and Light Company	39-0714890
	(a Wisconsin corporation)
	4902 N. Biltmore Lane
	Madison, Wisconsin 53718
	Telephone (608) 458-3311

This combined Form 8-K is separately filed by Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company.

_________________

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

[_]     Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

[_]     Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

[_]     Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

[_]     Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 5.02.      Departure of Directors or Principal Officers; Election of Directors; Appointment of Principal Officers.

        On May 4, 2005, Erroll B. Davis, Jr. provided notice to the Board of Directors that he will retire from Alliant Energy Corporation (the “Company”) no later than the date of the Company’s 2006 annual meeting and will step down as the Chief Executive Officer of the Company and its two utility subsidiaries, Interstate Power and Light Company (“IPL”) and Wisconsin Power and Light Company (“WPL”), effective July 1, 2005. Mr. Davis will continue to serve as Chairman of the Board.

        Also on May 4, 2005, the Board of Directors of the Company appointed William D. Harvey as the Chief Executive Officer of the Company, IPL and WPL, effective as of July 1, 2005. Mr. Harvey, 56, has served as President and Chief Operating Officer of the Company since January 2004, Chief Operating Officer of IPL and WPL since January 2004 and has been a director of the Company, IPL and WPL since January 2005. He previously served as Executive Vice President – Generation for the Company and IPL from 1998 to January 2004. He also previously served at WPL as President from 1998 to 2004, as Senior Vice President from 1993 to 1998, Vice President and General Counsel from 1990 to 1993 and Vice President and Associate General Counsel from 1986 to 1990. Terms of an employment agreement between the Company and Mr. Harvey have not been determined. Mr. Harvey’s appointment as Chief Executive Officer was part of the Company’s succession plan.

        The press release the Company issued announcing the changes discussed above is filed as Exhibit 99.1 and incorporated by reference herein.

Item 9.01.     Financial Statements and Exhibits.

(a) Not applicable.

(b) Not applicable

(c) Exhibits. The following exhibit is being filed herewith:

(99.1) Press Release dated May 4, 2005.

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SIGNATURES

        Pursuant to the requirements of the Securities Exchange Act of 1934, Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company have each duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	ALLIANT ENERGY CORPORATION
Date: May 4, 2005	By:  /s/ Barbara J. Swan
	Barbara J. Swan
	Executive Vice President and
	General Counsel
	INTERSTATE POWER AND LIGHT COMPANY
Date: May 4, 2005	By:  /s/ Barbara J. Swan
	Barbara J. Swan
	Executive Vice President and
	General Counsel
	WISCONSIN POWER AND LIGHT COMPANY
Date: May 4, 2005	By:  /s/ Barbara J. Swan
	Barbara J. Swan
	President

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EXHIBIT INDEX

Exhibit No. Description

99.1 Press Release dated May 4, 2005

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EX-99.1

Alliant Energy Corporation
Corporate Headquarters
4902 North Biltmore Lane
P.O. Box 77007
Madison, WI 53707-1007
www.alliantenergy.com

News Release
FOR IMMEDIATE RELEASE	Media Contact: Scott R. Smith (608) 458-3924
	Investor Relations Contact: Becky Johnson (608) 458-3267

DAVIS ANNOUNCES TRANSITION PLANS, HARVEY ELECTED CEO

MADISON, Wis. – May 4, 2005 – Erroll B. Davis, Jr., 60, Chairman and Chief Executive Officer of Alliant Energy (NYSE: LNT), announced today he will step down from his position as Chief Executive Officer July 1, 2005, and retire from the Board of Directors no later than the 2006 annual meeting. Mr. Davis will continue to serve as Chairman of the Board. Davis has served almost 27 years with Alliant Energy and its predecessor company, WPL Holdings.

As part of Alliant Energy’s succession plan, the Board of Directors today elected William D. Harvey, 56, as President and Chief Executive Officer, effective July 1, 2005. “Bill’s transition to CEO is consistent with the plan the Board put in place in January of 2004 reflecting the culmination of two years of planning.” said Davis. “This transition and the excellent team supporting Bill reflect the quality and depth of management we have in place at Alliant Energy.”

Davis joined the former Wisconsin Power and Light Co. in 1978 as Vice President-Finance. In 1984, he was promoted to Executive Vice President and was elected to the Board of Directors. He was then named President in 1987 and Chief Executive Officer in 1988. In 1990, he also became President and CEO of WPL Holdings, the parent company of WP&L. Prior to joining WP&L, he was on the corporate financial staffs of Ford Motor Co. and Xerox Corp.

In April 1998, Davis became the first President and CEO of Alliant Energy, a company formed as the result of a three-way merger between IES Industries, Inc., Interstate Power Co., and WPL Holdings, Inc. He became Chairman of the Board in April 2000. A native of Pittsburgh, PA, Davis has a B.S. in Electrical Engineering from Carnegie Mellon University and a MBA in Finance from the University of Chicago.

Davis is a member of the Board of Directors of the Edison Electric Institute and was Chair from June 2002 – June 2003. He also serves on the Boards of the Electric Power Research Institute, The Conference Board, and is a member of the Federal Reserve Bank of Chicago Advisory Board as well as the American Society of Corporate Executives where he serves as Chair. Davis is a Life Member and former Chairman of the Board of Trustees of Carnegie Mellon University and served on the University of Wisconsin System Board of Regents from 1987 – 1994.

Davis is a member of the Boards of Directors of BP p.l.c., PPG Industries, Union Pacific Corp., and the United States Olympic Committee.

(more)

Davis Announces Transition Plans, Harvey Elected CEO
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Harvey was elected President and Chief Operating Officer of Alliant Energy in January 2004. He was appointed to the Board of Directors in January, 2005.

Harvey joined WPL Holdings in 1986 as Vice President and Associate General Counsel. Since that time, he has successfully held a variety of positions including General Counsel and head of Gas Operations and Senior Vice President in charge of power production, gas operations, legal affairs and administrative services. Upon the formation of Alliant Energy in 1998, he was elected Executive Vice President in charge of generation and President of WP&L.

Prior to joining WPL Holdings, Harvey was in private legal practice in Madison, WI. A native of Sun Prairie, WI, Harvey received a B.A. in Economics and a Juris Doctorate from the University of Wisconsin-Madison.

Harvey serves on the Boards of the Meriter Foundation, Wisconsin Manufacturers and Commerce, the American Transmission Company, and the University of Wisconsin — Extension Board of Visitors.

Alliant Energy Corporation is an energy-services provider with subsidiaries serving more than three million customers. Providing its customers in the Midwest with regulated electricity and natural gas service remains the company’s primary focus. Alliant Energy’s domestic utility subsidiaries, Interstate Power and Light and Wisconsin Power and Light, serve 982,000 electric and 416,000 natural gas customers. Other business platforms include the international energy market and non-regulated domestic generation. Alliant Energy, headquartered in Madison, Wis., is a Fortune 1000 company traded on the New York Stock Exchange under the symbol LNT. For more information, visit the company’s Web site at www.alliantenergy.com.

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