Exhibit 32.2

                           SECTION 1350 CERTIFICATION
                         OF PRINCIPAL FINANCIAL OFFICER
                         (required by Section 906 of the
                           Sarbanes-Oxley Act of 2002)


In connection  with the report on Form 10-Q for the quarterly  period ended June
30, 2003 of Ameren  Corporation (the "Company") as filed with the Securities and
Exchange  Commission on the date hereof (the "Form 10-Q"),  I, Warner L. Baxter,
chief financial officer of the Company,  certify, pursuant to 18 U.S.C. ss.1350,
as adopted pursuant to ss.906 of the Sarbanes-Oxley Act of 2002, that:

(1)  The Form 10-Q fully  complies  with the  requirements  of Section  13(a) or
     15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)); and

(2)  The information contained in the Form 10-Q fairly presents, in all material
     respects, the financial condition and results of operations of the Company.

Dated:  August 14, 2003



                                        /s/ Warner L. Baxter
                                        ------------------------------
                                        Warner L. Baxter
                                        Senior Vice President, Finance
                                        (Principal Financial Officer)




A signed  original of this written  statement  required by Section 906, or other
document authenticating, acknowledging, or otherwise adopting the signature that
appears  in the  typed  form  within  the  electronic  version  of this  written
statement  required by Section 906, has been provided to Ameren  Corporation and
will be retained by Ameren  Corporation  and  furnished  to the  Securities  and
Exchange Commission or its staff upon request.