EXHIBIT F


                         [Steven R. Sullivan letterhead]


                               AMEREN CORPORATION
                              1901 Chouteau Avenue
                            St. Louis, Missouri 63166
                                  314-554-2098

                                February 27, 2003


Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, D.C. 20549

     Re:  Ameren Corporation, et al.
          Form U-1 Application-Declaration
          (File No. 70-10106)

Dear Sirs:

     I refer to the Form U-1 Application/Declaration, as amended, in the
above-referenced proceeding (the "Application"), under the Public Utility
Holding Company Act of 1935, as amended (the "Act"), filed with the Securities
and Exchange Commission (the "Commission") by Ameren Corporation ("Ameren"), a
registered holding company, its public-utility subsidiary companies: Union
Electric Company ("AmerenUE"), Central Illinois Public Service Company
("AmerenCIPS"), Central Illinois Light Company ("AmerenCILCO"), and Central
Illinois Generation, Inc. ("CIGI"); CILCORP Inc. ("CILCORP"), an exempt holding
company and a wholly-owned subsidiary of Ameren; and certain direct and indirect
wholly-owned non-utility subsidiary companies of Ameren, as named therein
(collectively, the "Applicants"). I have acted as counsel for Ameren and the
other Applicants in connection with the Application.

     Capitalized terms used herein that are not defined herein shall have the
meanings ascribed to them in the Application.

     As described in the Application, the Applicants are requesting
authorization for the period through March 31, 2006 (the "Authorization Period")
(1) to extend and restate the external short-term financing and interest rate
hedging authorization of AmerenUE and AmerenCIPS under the 1998 Financing Order,
(2) to extend and continue the Utility Money Pool and Non-Utility Money Pool (to
be re-designated as the "Non-Regulated Subsidiary Money Pool") arrangements, and
(3) to add AmerenCILCO as a participant in the Utility Money Pool and CILCORP,
CIGI, and certain direct and indirect non-utility subsidiaries of Ameren as
participants in the Non-Regulated Subsidiary Money Pool, in each case subject to




all of the existing terms, conditions and limitations of the money pool
agreements. These proposals are referred to collectively as the "Proposed
Transactions."

     In connection with the opinions given herein, I have examined original,
certified, or conformed copies of all such corporate records, agreements,
instruments, and documents and have made such other investigations as I have
deemed 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.

     The opinions expressed below with respect to the Proposed Transactions are
subject to the following assumptions and conditions:

     (a)  The Proposed Transactions shall have been duly authorized and
approved, to the extent required by the governing documents and applicable state
laws, by the Boards of Directors of Ameren and the other Applicants.

     (b)  The Commission shall have duly entered an appropriate order or orders
with respect to the Proposed Transactions as described in the Application
granting and permitting the Application to become effective under the Act and
the rules and regulations thereunder and the Proposed Transactions are
consummated in accordance with the Application and said order or orders.

     (c)  Ameren and the other Applicants shall have obtained all consents,
waivers and releases, if any, required for the Proposed Transactions under all
applicable governing corporate documents, contracts, agreements, debt
instruments, indentures, franchises, licenses and permits.

     (d)  No act or event other than as described herein shall have occurred
subsequent to the date hereof which would change the opinions expressed above.

     (e)  The consummation of the Proposed Transactions shall be conducted under
my supervision and all legal matters incident thereto shall be satisfactory to
me, including the receipt in satisfactory form of opinions of other counsel
qualified to practice in jurisdictions in which I am not admitted to practice,
as I may deem appropriate.

     Based on the foregoing, and subject to the assumptions and conditions set
forth herein, and having regard to legal considerations which I deem relevant, I
am of the opinion that, in the event the Proposed Transactions are consummated
in accordance with the Application:

     1.  Upon receipt by AmerenCILCO of an order of the Illinois Commerce
Commission authorizing it to participate in the Utility Money Pool, all state
laws applicable to the Proposed Transactions will have been complied with;

     2.  Ameren and the other Applicants are each validly organized and duly
existing under the laws of the states in which they are incorporated;


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     3.  The Short-term Debt, Interest Rate Hedges, and Anticipatory Hedges to
be issued or entered into by AmerenUE and AmerenCIPS, notes issued by AmerenUE
evidencing borrowings under the Utility Money Pool, and notes issued by CIGI
evidencing borrowings under the Non-Regulated Subsidiary Money Pool will be
valid and binding obligations of such companies in accordance with their terms;
and

     4.  The consummation of the Proposed Transactions will not violate the
legal rights of the holders of any securities issued by Ameren or any associate
company of Ameren.

     I hereby consent to the use of this opinion in connection with the
Application. The opinions given herein are intended solely for the benefit of
the Commission and may not be relied upon by any other person.


                                         Very truly yours,


                                         /s/ Steven R. Sullivan


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