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):

June 7, 2006

Commission File Number	Exact Name of Registrant as Specified in Charter; State of Incorporation; Address and Telephone Number	IRS Employer Identification Number
1-3672	Central Illinois Public Service Company (Illinois Corporation) 607 East Adams Street Springfield, Illinois 62739 (217) 523-3600	37-0211380
2-95569	CILCORP Inc. (Illinois Corporation) 300 Liberty Street Peoria, Illinois 61602 (309) 677-5271	37-1169387
1-2732	Central Illinois Light Company (Illinois Corporation) 300 Liberty Street Peoria, Illinois 61602 (309) 677-5271	37-0211050
1-3004	Illinois Power Company (Illinois Corporation) 370 South Main Street Decatur, Illinois 62523 (217) 424-6600	37-0344645

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.

Central Illinois Public Service Company, doing business as AmerenCIPS (“CIPS”), Central Illinois Light Company, doing business as AmerenCILCO (“CILCO”), and Illinois Power Company, doing business as AmerenIP (“IP”), each hereby file their Statement of Computation of Ratio of Earnings to Fixed Charges and Combined Fixed Charges and Preferred Stock Dividend Requirements for the three months ended March 31, 2006. CILCORP Inc. (“CILCORP”) hereby files its Statement of Computation of Ratio of Earnings to Fixed Charges for the three months ended March 31, 2006.

ITEM 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit Number:		Title:
12.1	CIPS	CIPS’ Statement of Computation of Ratio of Earnings to Fixed Charges and Combined Fixed Charges and Preferred Stock Dividend Requirements
12.2	CILCORP	CILCORP’s Statement of Computation of Ratio of Earnings to Fixed Charges
12.3	CILCO	CILCO’s Statement of Computation of Ratio of Earnings to Fixed Charges and Combined Fixed Charges and Preferred Stock Dividend Requirements
12.4	IP	IP’s Statement of Computation of Ratio of Earnings to Fixed Charges and Combined Fixed Charges and Preferred Stock Dividend Requirements

____________

This combined Form 8-K is being filed separately by Central Illinois Public Service Company, CILCORP Inc., Central Illinois Light Company and Illinois Power Company (each a “registrant”). Information contained herein relating to any individual registrant has been filed by such registrant on its own behalf. No registrant makes any representation as to information relating to any other registrant.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, each registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. The signature for each undersigned company shall be deemed to relate only to matters having reference to such company or its subsidiaries.

CENTRAL ILLINOIS PUBLIC SERVICE COMPANY

(Registrant)

/s/ Jerre E. Birdsong                                                

Name: Jerre E. Birdsong

Title: Vice President and Treasurer

CILCORP Inc.

(Registrant)

/s/ Jerre E. Birdsong                                                

Name: Jerre E. Birdsong

Title: Vice President and Treasurer

CENTRAL ILLINOIS LIGHT COMPANY

(Registrant)

/s/ Jerre E. Birdsong                                                 

Name: Jerre E. Birdsong

Title: Vice President and Treasurer

ILLINOIS POWER COMPANY

(Registrant)

/s/ Jerre E. Birdsong                                                  

Name: Jerre E. Birdsong

Title: Vice President and Treasurer

Date: June 7, 2006

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EXHIBIT INDEX

Exhibit Number:		Title:
12.1	CIPS	CIPS’ Statement of Computation of Ratio of Earnings to Fixed Charges and Combined Fixed Charges and Preferred Stock Dividend Requirements
12.2	CILCORP	CILCORP’s Statement of Computation of Ratio of Earnings to Fixed Charges
12.3	CILCO	CILCO’s Statement of Computation of Ratio of Earnings to Fixed Charges and Combined Fixed Charges and Preferred Stock Dividend Requirements
12.4	IP	IP’s Statement of Computation of Ratio of Earnings to Fixed Charges and Combined Fixed Charges and Preferred Stock Dividend Requirements

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