Mail Stop 3561 										January 10, 2006 Mr. William D. Harvey Chairman and Chief Executive Officer Alliant Energy Corporation 4902 N. Biltmore Lane Madison, Wisconsin 53718 		RE:	Alliant Energy Corporation 			Form 10-K for Fiscal Year Ended December, 2005 Form 10-Q for Fiscal Quarter Ended September 30, 2005 			Filed March 4, 2005 and November 8, 2005 File No. 1-9894 Dear Mr. Harvey: 	We have completed our review of your Form 10-K and related filings and have no further comments at this time. 								Sincerely, 									Jim Allegretto 									Senior Assistant Chief Accountant ?? ?? ?? ?? March 22, 2005 Page 1