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):



                                October 22, 2004



                               AMEREN CORPORATION
             (Exact name of registrant as specified in its charter)




           Missouri                      1-14756                43-1723446
(State or other jurisdiction           (Commission           (I.R.S. Employer
      of incorporation)                File Number)          Identification No.)




                 1901 Chouteau Avenue, St. Louis, Missouri 63103
              (Address of principal executive offices and Zip Code)




       Registrant's telephone number, including area code: (314) 621-3222






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))


<PAGE>


SECTION 2 - FINANCIAL INFORMATION

ITEM 2.02 Results of Operations and Financial Condition.

     On October 22, 2004, Ameren Corporation (the  "Registrant")  issued a press
release  announcing  its earnings for the quarterly  period ended  September 30,
2004. The press release is attached as Exhibit 99.1 and is  incorporated  herein
by reference.

     The information  furnished  pursuant to Item 2.02,  including Exhibit 99.1,
shall not be  deemed  "filed"  for  purposes  of  Section  18 of the  Securities
Exchange  Act  of  1934  (the  "Exchange  Act")  or  otherwise  subject  to  the
liabilities  under that  Section and shall not be deemed to be  incorporated  by
reference into any filing of the Registrant  under the Securities Act of 1933 or
the Exchange Act.



SECTION 9 - FINANCIAL STATEMENTS AND EXHIBITS

Item 9.01 Financial Statements and Exhibits.

(c)     Exhibits


<TABLE>
<CAPTION>
            <S>                 <C>
          -------------------------------------------------------------------------------------------
          | 99.1             |  Press release regarding earnings for the quarterly period ended     |
          |                  |  September 30, 2004, issued on October 22, 2004 by Ameren            |
          |                  |  Corporation                                                         |
          -------------------------------------------------------------------------------------------

</TABLE>








                                    SIGNATURE



Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
Registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned thereunto duly authorized.

                                  AMEREN CORPORATION
                                  (Registrant)


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





Date:  October 22, 2004


                                      -2-
<PAGE>



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

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

   99.1     - Press release regarding earnings for the quarterly period ended
              September 30, 2004, issued on October 22, 2004 by Ameren
              Corporation.
[{"type": "8-K", "sequence": "1", "filename": "ameren8k102204.txt", "description": "AMEREN8K 10-22-2004", "secsgml_size_bytes": 4295}]
{"company-data": {"conformed-name": "AMEREN CORP", "cik": "0001002910", "assigned-sic": "4931", "irs-number": "431723446", "state-of-incorporation": "MO", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "001-14756", "film-number": "041090733"}, "business-address": {"street1": "1901 CHOUTEAU AVE", "street2": "MC 1370", "city": "ST LOUIS", "state": "MO", "zip": "63166-6149", "phone": "314-621-3222"}, "mail-address": {"street1": "1901 CHOUTEAU AVE", "street2": "MC 1370", "city": "ST LOUIS", "state": "MO", "zip": "63103"}}
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):

                                October 22, 2004

                               AMEREN CORPORATION
             (Exact name of registrant as specified in its charter)

           Missouri                      1-14756                43-1723446
(State or other jurisdiction           (Commission           (I.R.S. Employer
      of incorporation)                File Number)          Identification No.)

                 1901 Chouteau Avenue, St. Louis, Missouri 63103
              (Address of principal executive offices and Zip Code)

       Registrant's telephone number, including area code: (314) 621-3222

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 2 - FINANCIAL INFORMATION

ITEM 2.02 Results of Operations and Financial Condition.

     On October 22, 2004, Ameren Corporation (the  "Registrant")  issued a press
release  announcing  its earnings for the quarterly  period ended  September 30,
2004. The press release is attached as Exhibit 99.1 and is  incorporated  herein
by reference.

     The information  furnished  pursuant to Item 2.02,  including Exhibit 99.1,
shall not be  deemed  "filed"  for  purposes  of  Section  18 of the  Securities
Exchange  Act  of  1934  (the  "Exchange  Act")  or  otherwise  subject  to  the
liabilities  under that  Section and shall not be deemed to be  incorporated  by
reference into any filing of the Registrant  under the Securities Act of 1933 or
the Exchange Act.

SECTION 9 - FINANCIAL STATEMENTS AND EXHIBITS

Item 9.01 Financial Statements and Exhibits.

(c)     Exhibits
-------------------------------------------------------------------------------------------
          | 99.1             |  Press release regarding earnings for the quarterly period ended     |
          |                  |  September 30, 2004, issued on October 22, 2004 by Ameren            |
          |                  |  Corporation                                                         |
          -------------------------------------------------------------------------------------------
SIGNATURE

Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
Registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned thereunto duly authorized.

                                  AMEREN CORPORATION
                                  (Registrant)

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

Date:  October 22, 2004

                                      -2-
Exhibit Index
                                  -------------

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

   99.1     - Press release regarding earnings for the quarterly period ended
              September 30, 2004, issued on October 22, 2004 by Ameren
              Corporation.