UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 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):
                                September 8, 2004





                 Exact Name of Registrant as specified in its charter;
Commission       State of Incorporation;                                        IRS Employer
File Number      Address and Telephone Number                                   Identification No.
-----------      ----------------------------                                   ------------------
                                                                           
1-14756          Ameren Corporation                                                43-1723446
                 (Missouri Corporation)
                 1901 Chouteau Avenue
                 St. Louis, Missouri 63103
                 (314) 621-3222

1-2967           Union Electric Company                                            43-0559760
                 (Missouri Corporation)
                 1901 Chouteau Avenue
                 St. Louis, Missouri 63103
                 (314) 621-3222

1-3672           Central Illinois Public Service Company                           37-0211380
                 (Illinois Corporation)
                 607 East Adams Street
                 Springfield, Illinois 62739
                 (217) 523-3600




333-56594        Ameren Energy Generating Company                                  37-1395586
                 (Illinois Corporation)
                 1901 Chouteau Avenue
                 St. Louis, Missouri 63103
                 (314) 621-3222

2-95569          CILCORP Inc.                                                      37-1169387
                 (Illinois Corporation)
                 300 Liberty Street
                 Peoria, Illinois 61602
                 (309) 677-5230

1-2732           Central Illinois Light Company                                    37-0211050
                 (Illinois Corporation)
                 300 Liberty Street
                 Peoria, Illinois 61602
                 (309) 677-5230




     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))





SECTION 8 - OTHER EVENTS
ITEM 8.01.  Other Events.

     On September 8, 2004,  Ameren  Corporation  (Ameren) issued a press release
announcing  that the  parties  participating  in the  case  pending  before  the
Illinois Commerce Commission (ICC) for approval of Ameren's proposed acquisition
of Illinois  Power Company (IP) from Dynegy Inc. have resolved all issues raised
in the proceeding. Ameren's proposed acquisition of IP is subject to approval by
the  ICC.  The  press  release  is  attached  hereto  as  Exhibit  99.1  and  is
incorporated herein by reference.


SECTION 9 - FINANCIAL STATEMENTS AND EXHIBITS
Item 9.01.  Financial Statements and Exhibits.

     (a)  Not applicable

     (b)  Not applicable

     (c)  Exhibits. The following exhibit is included with this Report:

     Exhibit
       No.          Description
     -------        -----------

       99.1         Press release dated September 8, 2004 regarding resolution
                    among parties in Illinois Commerce Commission case involving
                    Ameren's proposed acquisition of Illinois Power Company.


     This combined Form 8-K is being filed separately by Ameren,  Union Electric
Company,  Central  Illinois  Public Service  Company,  Ameren Energy  Generating
Company, CILCORP Inc. and Central Illinois Light 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.

                                       2





                                   SIGNATURES

     Pursuant to the  requirements of the Exchange Act, 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.


                                               AMEREN CORPORATION
                                                   (Registrant)

                                               /s/ Martin J. Lyons
                                    --------------------------------------------
                                                   Martin J. Lyons
                                          Vice President and Controller
                                          (Principal Accounting Officer)


                                              UNION ELECTRIC COMPANY
                                                   (Registrant)

                                               /s/ Martin J. Lyons
                                    --------------------------------------------
                                                   Martin J. Lyons
                                          Vice President and Controller
                                          (Principal Accounting Officer)


                                         CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
                                                    (Registrant)

                                               /s/ Martin J. Lyons
                                    --------------------------------------------
                                                   Martin J. Lyons
                                            Vice President and Controller
                                            (Principal Accounting Officer)


                                          AMEREN ENERGY GENERATING COMPANY
                                                      (Registrant)

                                               /s/ Martin J. Lyons
                                    --------------------------------------------
                                                   Martin J. Lyons
                                            Vice President and Controller
                                            (Principal Accounting Officer)



                                       3




                                                     CILCORP INC.
                                                    (Registrant)

                                                 /s/ Martin J. Lyons
                                    --------------------------------------------
                                                     Martin J. Lyons
                                              Vice President and Controller
                                              (Principal Accounting Officer)


                                           CENTRAL ILLINOIS LIGHT COMPANY
                                                    (Registrant)

                                               /s/ Martin J. Lyons
                                    --------------------------------------------
                                                   Martin J. Lyons
                                            Vice President and Controller
                                            (Principal Accounting Officer)



Date:  September 8, 2004


                                       4





                                  Exhibit Index
                                  -------------

Exhibit No.                       Description
-----------                       -----------

   99.1         Press release dated September 8, 2004 regarding resolution among
                parties in Illinois Commerce Commission case involving Ameren's
                proposed acquisition of Illinois Power Company.



                                       5



                                                                    Exhibit 99.1



[GRAPHIC OMITTED][GRAPHIC OMITTED]
                                                             One Ameren Plaza
                                                             1901 Chouteau
                                                             Avenue
                                                             St. Louis, MO 63103
Contact:

Media                      Analysts                Investors
Susan Gallagher            Bruce Steinke           Investor Services
(314) 554-2175             (314) 554-2574          (800) 255-2237
sgallagher@ameren.com      bsteinke@ameren.com     invest@ameren.com
                           -------------------

FOR IMMEDIATE RELEASE
---------------------

          AMEREN REACHES AGREEMENT IN ILLINOIS COMMERCE COMMISSION CASE
                      INVOLVING ILLINOIS POWER ACQUISITION

     St.  Louis,  Mo.,  Sept. 8,  2004---Ameren  Corporation  (NYSE:  AEE) today
announced  that parties  participating  in its case pending  before the Illinois
Commerce  Commission (ICC) for the approval of Ameren's proposed  acquisition of
Illinois  Power Company have resolved all issues raised in the  proceeding.  The
terms  of the  resolution  of  these  issues  are  consistent,  in all  material
respects,  with Ameren's  expectations  at the time it entered into the proposed
acquisition of Illinois Power Company.

     This transaction, including the ultimate resolution of the issues raised in
this proceeding by the parties,  is subject to approval by the ICC.  Information
related   to   the   case   can  be   obtained   from   the   ICC   website   at
http://www.icc.state.il.us.
--------------------------

     Ameren  announced on Feb. 3, 2004, the proposed $2.3 billion  purchase from
Dynegy Inc.  (NYSE:  DYN) of the stock of  Decatur,  Ill.-based  Illinois  Power
Company and Dynegy's 20 percent  interest in Electric  Energy,  Inc., owner of a
Joppa,  Ill.,  coal-fired  power  plant.  Ameren has  received  approval  of the
acquisition  from the  Federal  Energy  Regulatory  Commission  and the  Federal
Communications   Commission.   In  addition,   the  waiting   period  under  the
Hart-Scott-Rodino  Act expired without a request by the Federal Trade Commission
and  the  Antitrust  Division  of  the  Department  of  Justice  for  additional
information or documents.  Ameren's completion of this acquisition also requires
approval  from the U.S.  Securities  and Exchange  Commission,  under the Public
Utility  Holding  Company  Act of 1935,  and is  subject  to  customary  closing
conditions.

     Ameren  Executive  Vice  President and Chief  Financial  Officer  Warner L.
Baxter will speak Wednesday, Sept. 8, at 9:45 a.m. (EDT) at Lehman Brothers 2004
CEO Energy/Power  Conference.  He will present an overview of Ameren's financial
performance  and  business  strategy,  including  information  related to the IP
acquisition process.

                                   -- more --

Add One

     This discussion will be available on a live audio Webcast from 9:45 a.m. to
10:20 a.m. (EDT) via a link on the  Investors/Presentations  section of Ameren's
Web site, www.ameren.com.  It will be available approximately one hour after the
presentation  for one year.  Slides for the  presentation  will be posted on the
Ameren Web site.

     With  assets  of $14.7  billion,  Ameren  owns a  diverse  mix of  electric
generating plants strategically located in its Midwest market with a capacity of
more than 14,600  megawatts.  Ameren serves 1.7 million  electric  customers and
500,000  natural gas  customers  in a 49,000  square-mile  area of Missouri  and
Illinois.

Forward-Looking Statements
--------------------------

     Statements made in this release,  which are not based on historical  facts,
are  "forward-looking"  and,  accordingly,  involve risks and uncertainties that
could cause actual results to differ  materially from those discussed.  Although
such "forward-looking"  statements have been made in good faith and are based on
reasonable assumptions,  there is no assurance that the expected results will be
achieved.  These statements include (without limitation) statements as to future
expectations,  beliefs, plans, strategies,  objectives,  events, conditions, and
financial  performance.  In connection with the "safe harbor"  provisions of the
Private Securities  Litigation Reform Act of 1995, the company is providing this
cautionary  statement  to identify  important  factors  that could cause  actual
results to differ materially from those anticipated.  The following factors,  in
addition to those discussed elsewhere in this release and in past and subsequent
filings with the Securities and Exchange Commission,  could cause actual results
to  differ  materially  from  management   expectations  as  suggested  by  such
"forward-looking" statements:

o    the closing and timing of Ameren's  acquisition  of Illinois  Power and the
     impact of any  conditions  imposed by regulators  in connection  with their
     approval thereof;
o    difficulties in integrating AmerenCILCO and Illinois Power, if consummated,
     with Ameren's other businesses; and
o    changes in the energy markets, environmental laws or regulations,  interest
     rates or other factors adversely  impacting  assumptions in connection with
     the CILCORP and Illinois Power (if consummated) acquisitions.

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