35-CERT

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549



- -----------------------------------------------------
IN THE MATTER OF                                                     CERTIFICATE
AMEREN CORPORATION, ET AL.                                           PURSUANT TO
                                                                     RULE 24
File No. 70-10180

(Public Utility Holding Company Act of 1935)
- -----------------------------------------------------


     This Certificate of Notification pursuant to Rule 24 under the Public
Utility Holding Company Act of 1935, as amended (the "Act"), is filed by Ameren
Corporation ("Ameren"), a registered holding company, and its wholly-owned
public utility subsidiaries, Union Electric Company, d/b/a AmerenUE ("AmerenUE")
and Central Illinois Public Service Company, d/b/a AmerenCIPS ("AmerenCIPS"), in
connection with (1) the transfer of AmerenUE's electric transmission and
distribution system and gas distribution system located in Illinois ("Illinois
Utility System")to AmerenCIPS and, as consideration for the purchased assets,
AmerenCIPS' issuance of its subordinated promissory note ("AmerenCIPS Note") to
AmerenUE, and (2) AmerenUE's acquisition for cash of the Kinmundy and
Pinckneyville, Illinois, electric generating stations owned by Ameren Energy
Generating Company ("Ameren Genco").

     Ameren, AmerenUE and AmerenCIPS hereby certify to the Commission pursuant
to Rule 24 that, on May 2, 2005: (i) AmerenUE transferred the Illinois Utility
System to AmerenCIPS at a net book value of approximately $138 million by means
of a sale of a 50% undivided interest in the Illinois Utility System and an
in-kind dividend to Ameren of the remaining 50% undivided interest followed
immediately by Ameren's contribution of such undivided interest to AmerenCIPS,
(ii) as consideration for the portion of the Illinois Utility System that it
purchased, Ameren CIPS issued and delivered the AmerenCIPS Note to AmerenUE in
the principal amount of approximately $69 million, such note having a maturity
of five years and bearing interest at 4.70% per annum, and (iii) AmerenUE
purchased the Kinmundy and Pinckneyville electric generating stations from
Ameren Genco for an aggregate net book value of approximately $240 million.

         Ameren, AmerenUE, AmerenCIPS and Ameren Genco have heretofore filed a
Current Report on Form 8-K pursuant to the Securities Exchange Act of 1934, as
amended (File Nos. 1-14756, 1-2967, 1-3672 and 333-56594) containing a more
complete description of the closing transactions on May 2, 2005 and certain
post-closing matters.

     A "past tense" opinion of counsel is filed as Exhibit F-1 hereto.





                                   SIGNATURES

     Pursuant to the requirements of the Act, the undersigned companies have
duly caused this certificate to be signed on their behalves by the undersigned
thereunto duly authorized.


                                       Ameren Corporation
                                       Union Electric Company
                                       Central Illinois Public Service Company


                                       By: /s/  Steven R. Sullivan
                                           -------------------------------------
                                       Name:    Steven R. Sullivan
                                       Title:   Senior Vice President, General
                                                Counsel and Secretary


Dated:  May 3, 2005


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EX-99

                                                                     EXHIBIT F-1

                 [On Letterhead of Steven R. Sullivan, Esquire]

                                                                     May 3, 2005


Securities and Exchange Commission
450 Fifth Street, NW
Washington, DC 20549

     Re:  Ameren Corporation, et al. - File No. 70-10180

Dear Sirs:

     I am Senior Vice President, General Counsel and Secretary of Ameren
Corporation ("Ameren"), a registered public utility holding company under the
Public Utility Holding Company Act of 1935, as amended (the "Act"), and of its
wholly-owned subsidiaries, Union Electric Company ("AmerenUE") and Central
Illinois Public Service Company ("AmerenCIPS"). I am furnishing this opinion in
connection with the Application/Declaration filed on Form U-1 jointly by Ameren,
AmerenUE and AmerenCIPS (collectively referred to as the "Applicants") and the
order of the Commission dated April 19, 2005 (the "Order") approving the
Application/Declaration. I am an attorney licensed to practice law in the State
of Missouri and have acted as counsel for the Applicants in connection with the
Application.

     In the Application, the Applicants requested authorization for (a) AmerenUE
to sell and transfer to AmerenCIPS all of AmerenUE's electric transmission and
distribution assets and franchises located in Illinois (other than certain
generation assets and related facilities), and AmerenUE's retail gas
distribution facilities and franchises in Illinois (together, the "Acquired
Assets"), (b) AmerenCIPS to issue its promissory note to AmerenUE as
consideration for the purchased portion of the Acquired Assets, and (c) AmerenUE
to acquire, for cash, two electric generating plants, the Pinckneyville Plant
and the Kinmundy Plant, located in Illinois, which were previously owned by
Ameren Energy Generating Company, an "exempt wholesale generator" under the Act
(together, the "Authorized Transactions"). The Authorized Transactions were
consummated on May 2, 2005.

     In connection with this opinion, I have examined the original, certified,
or conformed copies of the Application/Declaration and the Order, all relevant
corporate records, agreements, instruments and documents of the Applicants and
certificates of public officials and officers of the Applicants, and have made
such other investigations, as I have deemed to be necessary or appropriate for
the purpose of rendering this opinion. In my examination, I have assumed the
genuineness of all signatures, the authenticity of all documents submitted to me
as originals, and the conformity to originals of all documents submitted to me
as conformed copies.

     Based on the foregoing, and having regard to legal considerations which I
deem relevant, I am of the opinion that:





     1. All state laws applicable to the Authorized Transactions have been
complied with.

     2. The Applicants are validly organized and duly existing under the laws of
their respective states of incorporation.

     3. The promissory note issued by AmerenCIPS in consideration for the
purchased portion of the Acquired Assets is a valid and binding obligation of
AmerenCIPS.

     4. AmerenCIPS has legally acquired the Acquired Assets and AmerenUE has
legally acquired AmerenCIPS' promissory note. AmerenUE has legally acquired the
Pinckneyville Plant and the Kinmundy Plant.

     5. The consummation of the Authorized Transactions did not violate the
legal rights of the holder of any securities issued by any of the Applicants.

     I hereby consent to the filing of this opinion with the Applicants'
certificate pursuant to Rule 24 in the above-referenced proceeding. The opinions
expressed herein are intended solely for the benefit of the Commission, and may
not be relied upon for any purpose by any other person.

                                       Sincerely,

                                       /s/ Steven R. Sullivan
                                       -----------------------------------------
                                       Steven R. Sullivan


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