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

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FORM 8-K

CURRENT REPORT

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

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Date of Report
(Date of earliest
event reported):	July 5, 2005

Commission	Name of Registrant, State of Incorporation, Address of	IRS Employer
File Number	Principal Executive Offices and Telephone Number	Identification Number
0-4117-1	Interstate Power and Light Company	42-0331370
	(an Iowa corporation)
	Alliant Energy Tower
	Cedar Rapids, Iowa 52401
	Telephone (319) 786-4411

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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 8.01.     Other Events.

        On July 5, 2005, Interstate Power and Light Company (the “Company”) announced that it had signed a definitive agreement to sell its 70% ownership interest in the 598 megawatt Duane Arnold Energy Center, a nuclear generating facility located near Palo, Iowa, to FPL Energy, LLC, a subsidiary of FPL Group, Inc. The press release the Company issued announcing the definitive sale agreement 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 July 5, 2005.

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SIGNATURES

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

	INTERSTATE POWER AND LIGHT COMPANY6
	By:  /s/ John E. Kratchmer
Date:  July 5, 2005	John E. Kratchmer
	Vice President-Controller and
	Chief Accounting Officer

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EXHIBIT INDEX

Exhibit No.	Description
99.1	Press Release dated July 5, 2005

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