SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549


In the Matter of:                                 QUARTERLY CERTIFICATE PURSUANT
                                                  PURSUANT TO RULE 24 UNDER THE
AMEREN CORPORATION,                               PUBLIC UTILITY HOLDING COMPANY
    and its Subsidiaries                          ACT OF 1935


File Nos.  70-9877, 70-10078, 70-10106, 70-9427

================================================================================

     Ameren Corporation  ("Ameren"),  a registered holding company, on behalf of
itself and its subsidiaries,  hereby files this certificate  pursuant to Rule 24
reporting on  transactions  authorized by the Commission by orders dated October
5, 2001 (Holding Co. Act Release No. 27449),  February 27, 2003 (Holding Co. Act
Release No. 27655),  January 29, 2003 (Holding Co. Act Release No.  27645),  and
July 23, 1999 (Holding Co. Act Release No.  27053).  This  certificate  is filed
with respect to transactions  consummated  during the quarter ended December 31,
2003.

A.   Financing by Ameren (File No. 70-9877):
     -------------------

     1.   Sales of any Common  Stock by Ameren  (other  than  pursuant  to Stock
          Plans) and the purchase price per share and the market price per share
          at the date of the agreement of sale.

          No such sales occurred during the 4th quarter of 2003.


     2.   The total number of shares of Common  Stock  issued or issuable  under
          options,  warrants or other  stock-purchase  rights granted during the
          quarter under Stock Plans.

          Dividend Reinvestment and Stock Purchase Plan:     422,791
          Long Term Savings Plan 148 AmerenCIPS:               7,315
          Long Term Savings Plan 702 AmerenCIPS:              10,036
          Long Term Savings Plan AmerenCILCO                  13,015 (estimated)
          Savings Investment Plan Ameren                     108,194
          Long Term Incentive Plan (Restricted Common Stock)       0

          Total                                              561,351


     3.   If Common Stock has been  transferred  to a seller of  securities of a
          company being acquired,  the number of shares so issued, the value per
          share and whether the shares are restricted to the acquiror.

          N/A


     4.   The amount and terms of any Long-term  Debt,  Preferred Stock or other
          preferred or equity-linked  securities  issued by Ameren,  directly or
          indirectly  through  a  Financing  Subsidiary,   during  the  calendar
          quarter.

          No such securities were issued during the 4th quarter of 2003.



     5.   The  amount  and  terms of any  Short-term  Debt  issued  directly  or
          indirectly by Ameren during the calendar quarter.

          A.   There was no  commercial  paper issued  during the 4th quarter of
               2003.

          B.   There were no bank loans during the 4th quarter of 2003.

          Maximum indebtedness at any one time:  $0.


          6.   A description  of the amount,  terms and purpose of any Guarantee
               issued during the calendar  quarter by Ameren and the name of the
               beneficiary of such Guarantee.




               Parent          Subsidiary                            Amount                     Terms               Purpose
               ------          ----------                            ------                     -----               -------
                                                                                                    
               Ameren Corp.    Ameren Energy Marketing               $ 1,000,000          12/01/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 2,000,000          11/06/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 5,000,000          10/31/03-12/31/04      Credit  Support
               Ameren Corp.    CILCORP Energy Services Inc.          $ 3,000,000          11/05/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 1,000,000          10/21/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 2,000,000          10/31/03-12/31/04      Credit Support
               Ameren Corp.    CILCORP Energy Services Inc.          $   190,000          10/15/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 1,000,000          11/10/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 1,000,000          11/21/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 1,000,000          12/12/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 1,000,000          10/14/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 1,000,000          10/31/03-12/31/04      Credit Support
               Ameren Corp.    CILCORP Energy Services Inc.          $ 3,000,000          12/12/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 1,500,000          10/28/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 1,000,000          11/13/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Fuels & Services Co.    $ 0                  12/31/02-12/31/03      Credit Support
               Ameren Corp.    Ameren Energy Fuels & Services Co.    $ 5,000,000          10/21/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 2,000,000          10/15/03-12/31/04      Credit Support
               Ameren Corp.    Ameren Energy Marketing               $ 0                  02/20/02-12/31/03      Credit Support





          7.   The  name  and  amount   invested  by  Ameren  in  any  Financing
               Subsidiary during the calendar quarter.

               N/A


          8.   The notional  amount and  principal  terms of any  Interest  Rate
               Hedge or  Anticipatory  Hedge  entered into by Ameren  during the
               quarter and the identity of the parties to such instruments.

               No such  agreements  were  entered into during the 4th quarter of
               2003.


          9.   Consolidated  balance  sheet  of  Ameren  as of  the  end  of the
               calendar quarter.

               Incorporated  by reference  to the Annual Report on Form 10-K for
               the fiscal year ended December 31, 2003 in File No. 1-14756.


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B.   Financing by CILCORP and Utility Subsidiaries (File Nos.70-10106 and
     ---------------------------------------------  70-10078):

          1.   The type of long-term  securities (e.g., common stock,  long-term
               debt,   preferred   securities,   etc.)   issued  by  CILCORP  or
               AmerenEnergy  Resources  Generating  Company (AERG) f/k/a Central
               Illinois Generation Inc. (CIGI) during the quarter and the amount
               of consideration received.

               No such securities were issued during the 4th quarter of 2003.



          2.   The principal  terms (e.g.,  interest  rate,  maturity,  dividend
               rate, sinking fund provisions,  etc.) of any long-term securities
               issued by CILCORP or AERG during the quarter.

               N/A



          3.   The amount and terms of any  Short-term  Debt  issued by CILCORP,
               AmerenUE, AmernCIPS,  AmerenCILCO or AERG (other than through the
               Utility Money Pool) during the calendar quarter.

               AmerenUE issued  commercial  paper during the 4th quarter of 2003
               through A. G.  Edwards,  Goldman  Sachs,  and/or Bank One Capital
               Markets,  ranging up to $150.0  million,  at an average  interest
               rate of  1.14%.  No  Short-Term  Debt  was  issued  by the  other
               identified  entities  during the 4th  quarter of 2003 (other than
               through the Utility Money Pool).

               There were no bank loans during the 4th quarter of 2003.

               Maximum indebtedness at any one time: $150.0 million on 12/31/03.


          4.   If  payment  of any debt  securities  may be  accelerated  by the
               holders  thereof by reason of a default by any associate  company
               of the issuer  under any  obligation  of such  associate  company
               (i.e., a cross default),  the identity of such associate  company
               and the nature of obligation  of the  associate  company to which
               the cross default relates.

               There exists a cross default provision in the indenture  relating
               to CILCORP's 8.70% and 9.375% senior unsecured notes,  whereby an
               event of default  would be triggered if there is a default in the
               payment  of  the  principal  under  any  mortgage,  indenture  or
               instrument  under which there may be issued or by which there may
               be secured or evidenced any  indebtedness  for borrowed  money of
               any  significant  subsidiary.  Default  must be for an  aggregate
               amount exceeding $25 million. This would apply to any outstanding
               short-term  or  long-term  AmerenCILCO  indebtedness,   including
               funded bank loans.



          5.   The amount and purpose of any Guarantee issued by CILCORP.



               Parent          Subsidiary                            Amount                     Terms               Purpose
               ------          ----------                            ------                     -----               -------
                                                                                                   
              CILCORP          CILCORP Energy Services, Inc.         $2,000,000            01/01/03-12/31/03    Credit Support



          6.   The notional  amount and  principal  terms of any  Interest  Rate
               Hedge or  Anticipatory  Hedge  entered into during the quarter by
               CILCORP,  AmerenUE,  AmerenCIPS,  AmerenCILCO  or  AERG  and  the
               identity of the parties to such instruments.

               No such  agreements  were  entered into during the 4th quarter of
               2003.


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          7.   With respect to each Financing Subsidiary that has been formed by
               CILCORP, AmerenCILCO or AERG, a representation that the financial
               statements  of the  parent  company of the  Financing  Subsidiary
               shall  account for the Financing  Subsidiary  in accordance  with
               generally  accepted  accounting   principles  and  further,  with
               respect  to  each  such  entity,  (i) the  name of the  Financing
               Subsidiary,  (ii) the amount  invested  by the parent  company in
               such Financing Subsidiary;  (iii) the balance sheet account where
               the investment  and the cost of the  investment are booked;  (iv)
               the form of organization (e.g., corporation, limited partnership,
               trust,  etc.) of such  Financing  Subsidiary;  (v) the percentage
               owned by the parent company;  and (vi) if any equity interests in
               the Financing Subsidiary are sold in a non-public  offering,  the
               identity of the purchasers.


               N/A

          8.   Consolidated  balance  sheets of AmerenUE,  AmerenCIPS,  CILCORP,
               AmerenCILCO and AERG as of the end of the calendar quarter, which
               may be  incorporated  by  reference  to filings,  if any, by such
               companies under the Securities Act of 1933 or Securities Exchange
               Act of 1934.


               Incorporated  by reference to the combined  Annual Report on Form
               10-K for the fiscal year ended  December  31, 2003 to be filed by
               the following companies:  AmerenUE in File No. 1-2967, AmerenCIPS
               in File No. 1-3672,  CILCORP in File No. 2-95569, and AmerenCILCO
               in File No. 1-2732. AERG did not become operational until October
               3, 2003 when AmerenCILCO's  generating assets were transferred to
               it. Consequently, AERG's balance sheet as of December 31, 2003 is
               not being provided with this report.





C.   Money Pole Transactions (File No. 70-10106):
     -----------------------
           
          1.   The maximum  outstanding  amount of all borrowings from and loans
               to the Utility Money Pool by each Utility Money Pool  participant
               during  the  quarter,  and the rate or range of rates  charged on
               Utility  Money Pool  borrowings  and paid on  Utility  Money Pool
               investments during the quarter.

               Maximum contribution/investment for AmerenUE - $22.7 million
               Maximum contribution/investment for AmerenCIPS - $16.8 million
               Maximum contribution/investment for AmerenCILCO - $0.0
               Maximum contribution/investment for Ameren Corporation - $468.1 million

               Maximum borrowing for Ameren Services - $61.2 million
               Maximum borrowing for AmerenUE - $266.9 million
               Maximum borrowing for AmerenCIPS - $121.5 million
               Maximum borrowing for AmerenCILCO - $230.2 million

               Average interest rate for the Utility Money Pool for the quarter: 1.02%


          2.   The maximum  outstanding  amount of all borrowings from and loans
               to the Non-Regulated  Subsidiary Money Pool by each Non-Regulated
               Subsidiary  Money Pool  participant  during the quarter,  and the
               rate or range of rates charged on Non-Regulated  Subsidiary Money
               Pool borrowings and paid on  Non-Regulated  Subsidiary Money Pool
               investments during the quarter.

               Maximum contribution/investment for Ameren Corporation - $328.2 million
               Maximum contribution/investment for Ameren Energy Fuels & Services - $1.0 million
               Maximum contribution/investment for Ameren Energy Marketing - $42.6 million
               Maximum contribution/investment for CILCORP Energy Services - $3.7 million
               Maximum contribution/investment for CIPSCO Investment Co. - $1.5 million
               Maximum contribution/investment for Union Electric Development - $0.2 million


                                       4





           
               Maximum borrowing for Ameren Energy Fuels and Services - $34.9 million
               Maximum borrowing for Ameren Development - $1.5 million
               Maximum borrowing for Ameren Energy Communications - $30.0 million
               Maximum borrowing for Ameren Energy Development - $27.0 million
               Maximum borrowing for Ameren Energy Generating - $211.1 million
               Maximum borrowing for Ameren Energy Resources - $5.9 million
               Maximum borrowing for Ameren Energy - $11.5 million
               Maximum borrowing for CIPSCO Investment Co. - $5.4 million
               Maximum borrowing for Ameren ERC - $16.8 million
               Maximum borrowing for Illinois Materials Supply - $4.3 million
               Maximum borrowing for Ameren Energy Marketing - $31.6 million
               Maximum borrowing for Union Electric Development - $3.1 million
               Maximum borrowing for AERG - $18.2 million
               Maximum borrowing for Medina Valley - $37.1 million

               Average interest rate for the Non-Regulated Subsidiary Money Pool for the quarter: 8.8%




D.   Other Transactions Involving Ameren's Nonutility Subsidiaries
     -------------------------------------------------------------
     (File No. 70-9427):

1.   Balance Sheet and Income Statement for each Intermediate Subsidiary for the
     three, six or nine month period ended.

     No financial statements are required for the fourth quarter filing.


2.   Information  concerning  the nature and extent of services  provided by any
     Nonutility Subsidiary that is authorized or permitted under the Act to sell
     goods and services during the quarter, identifying the associate company to
     which such  services  are sold,  the service  and the  charge,  and stating
     whether the charge was  computed at cost,  market or by another  method (as
     specified herein).

     To be filed confidentially under Rule 104.


3.   Information  concerning  the completion of any  reorganization  of Ameren's
     ownership in  Intermediate  Subsidiaries  and/or  Nonutility  Subsidiaries,
     including the identity of the companies involved and their line of business
     and corporate structure both before and after the reorganization.

     N/A



     The undersigned  registered  holding company has duly caused this quarterly
report to be signed on its  behalf by the  undersigned  officer  thereunto  duly
authorized  pursuant to the  requirements  of the Public Utility Holding Company
Act of 1935.

Ameren Corporation




By       /s/ Jerre E. Birdsong                     Date: February 25, 2004
-------------------------------------
             Jerre E. Birdsong
       Vice President and Treasurer


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