UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549
                                    FORM 10-K/A

                (X) ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

                   FOR THE FISCAL YEAR ENDED DECEMBER 31, 2002
                                                          OR
              ( ) Transition report pursuant to Section 13 or 15(d)
                     of the Securities Exchange Act of 1934
                For the transition period from ______to _______.

                          COMMISSION FILE NUMBER 1-2967

                             UNION ELECTRIC COMPANY
             (Exact name of registrant as specified in its charter)

         Missouri                                    43-0559760
(State or other jurisdiction of             (I.R.S. Employer Identification No.)
  incorporation or organization)

                 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

           Securities Registered Pursuant to Section 12(b) of the Act:

Title of each class                    Name of each exchange on which registered
- -------------------                    -----------------------------------------
Preferred Stock, without par value
(entitled to cumulative dividends):
       Stated value $100 per share -   }
         $4.56 Series                  }
         $4.50 Series                  }               New York Stock Exchange
         $4.00 Series                  }
         $3.50 Series                  }

        Securities Registered Pursuant to Section 12(g) of the Act: None.

     Indicate  by check mark  whether the  registrant  (1) has filed all reports
required to be filed by Section 13 or 15(d) of the  Securities  Exchange  Act of
1934  during  the  preceding  12 months  (or for such  shorter  period  that the
registrant was required to file such reports),  and (2) has been subject to such
filing requirements for the past 90 days. Yes ( X ). No ( ).

     Indicate by check mark if disclosure of delinquent  filers pursuant to Item
405 of Regulation S-K is not contained,  and will not be contained,  to the best
of  registrant's  knowledge,  in  definitive  proxy  or  information  statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. ( ).

     Indicate by check mark whether the registrant is an  accelerated  filer (as
defined in Rule 12b-2 of the Securities Exchange Act of 1934). Yes ( ). No (X).

     As of June 28, 2002,  Ameren  Corporation held all 102,123,834  outstanding
shares of common stock, $5 par value, of Union Electric  Company.  The aggregate
market  value  of the  voting  preferred  stock,  without  par  value,  held  by
non-affiliates  of Union  Electric  Company at June 28, 2002,  based on the last
reported sale price on the New York Stock  Exchange  composite tape on that date
(excluding  Preferred  Stock for which  quotes are not publicly  available)  was
$47,998,478.

     Shares of Common  Stock,  $5 par value,  outstanding  as of March 21, 2003:
102,123,834 shares (all owned by Ameren Corporation).

                      Documents incorporated by references.

     Portions of the registrant's definitive proxy statement for the 2003 annual
meeting are incorporated by reference into Part III.




                                EXPLANATORY NOTE

     All  documents  identified as being filed with our Form 10-K for the fiscal
year ended  December  31, 2002 were filed except  Exhibit No. 12.1  Statement of
Computation  of Ratio of Earnings to Fixed Charges and Preferred  Stock Dividend
Requirements which is being filed with this amendment to Form 10-K.


                                     PART IV

ITEM 15. EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K.


     (C) Exhibits.

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

      3.1(i)       Restated Articles of Incorporation of Union Electric Company
                   d/b/a AmerenUE (AmerenUE), as filed with the Secretary of
                   State of the State of Missouri (1993 Form 10-K, Exhibit
                   3(i)).

      3.2(ii)      By-Laws of AmerenUE as amended to August 23, 2001 (September
                   30, 2001 Form 10-Q, Exhibit 3(ii)).

      4.2          Order of the Securities and Exchange Commission dated
                   October 16, 1945 in File No. 70-1154 permitting the issue of
                   Preferred Stock, $3.70 Series (File No. 2-27474, Exhibit
                   3-E).

      4.3          Order of the Securities and Exchange Commission dated April
                   30, 1946 in File No. 70-1259 permitting the issue of
                   Preferred Stock, $3.50 Series (File No. 2-27474, Exhibit
                   3-F).

      4.4          Order of the Securities and Exchange Commission dated
                   October 20, 1949 in File No. 70-2227 permitting the issue of
                   Preferred Stock, $4.00 Series (File No. 2-27474, Exhibit
                   3-G).

      4.5          Indenture of Mortgage and Deed of Trust of AmerenUE dated
                   June 15, 1937 (AmerenUE Mortgage), as amended May 1,
                   1941, and Second Supplemental Indenture dated May1, 1941
                   (File No. 2-4940, Exhibit B-1).

      4.6          Supplemental Indentures to the AmerenUE Mortgage

                   Dated as of            File Reference            Exhibit No.
                   -----------            --------------            ----------
                    April 1, 1971          Form 8-K, April 1971            6
                    February 1, 1974       Form 8-K, February 1974         3
                    July 7, 1980           2-69821                         4.6
                    December 1, 1991       33-45008                        4.4
                    December 4, 1991       33-45008                        4.5
                    January 1, 1992        Form 10-K, 1991                 4.6
                    October 1, 1992        Form 10-K, 1992                 4.6
                    December 1, 1992       Form 10-K, 1992                 4.7
                    February 1, 1993       Form 10-K, 1992                 4.8
                    May 1, 1993            Form 10-K, 1993                 4.6
                    August 1, 1993         Form 10-K, 1993                 4.7
                    October 1, 1993        Form 10-K, 1993                 4.8
                    January 1, 1994        Form 10-K, 1993                 4.9
                    February 1, 2000       Form 10-K, 2000                 4.1
                    August 15, 2002        Form 8-K, August 22, 2002       4.3
                    March 5, 2003          Form 8-K, March 10, 2003        4.4

      4.7           Indenture (for unsecured subordinated debt securities) of
                    AmerenUE dated as of December 1, 1996 (1996 Form 10-K,
                    Exhibit 4.36).

      4.8           Loan Agreement dated as of December 1, 1991 between the
                    State Environmental Improvement and Energy Resources
                    Authority and AmerenUE, together with Indenture of Trust
                    dated as of December 1, 1991 between the Authority and
                    UMB Bank, N.A. as successor trustee (1992 Form 10-K, Exhibit
                    4.37).
                                       2


         Exhibit No.                           Description
         -----------                           -----------
      4.9           Loan Agreement dated as of December 1, 1992, between the
                    State Environmental Improvement and Energy Resources
                    Authority and AmerenUE, together with Indenture of Trust
                    dated as of December 1, 1992 between the Authority and
                    UMB Bank, N.A. as successor trustee (1992 Form 10-K, Exhibit
                    4.38).

      4.10          Fuel Lease dated as of February 24, 1981 between AmerenUE,
                    as lessee, and Gateway Fuel Company, as lessor, covering
                    nuclear fuel (1980 Form 10-K, Exhibit 10.20).


      4.11          Amendments to Fuel Lease dated as of May 8, 1984 and October
                    15, 1984, respectively, between AmerenUE, as lessee, and
                    Gateway Fuel Company, as lessor, covering nuclear fuel
                    (Registration No. 2-96198, Exhibit 4.28).

      4.12          Amendment to Fuel Lease dated as of October 15, 1986 between
                    AmerenUE, as lessee, and Gateway Fuel Company, as lessor,
                    covering nuclear fuel (September 30, 1986 Form 10-Q, Exhibit
                    4.3).

      4.13          Series 1998A Loan Agreement dated as of September 1, 1998
                    between The State Environmental Improvement and Energy
                    Resources Authority of the State of Missouri and AmerenUE
                    (September 30, 1998 Form 10-Q, Exhibit 4.28).

      4.14          Series 1998B Loan Agreement dated as of September 1, 1998
                    between The State Environmental Improvement and Energy
                    Resources Authority of the State of Missouri and AmerenUE
                    (September 30, 1998 Form 10-Q, Exhibit 4.29).

      4.15          Series 1998C Loan Agreement dated as of September 1, 1998
                    between The State Environmental Improvement and Energy
                    Resources Authority of the State of Missouri and AmerenUE
                    (September 30, 1998 Form 10-Q, Exhibit 4.30).


      4.16          Indenture dated as of August 15, 2002, from AmerenUE to The
                    Bank of New York, as Trustee, relating to senior secured
                    debt securities (including the forms of senior secured debt
                    securities as exhibits) (Form 8-K dated August 22, 2002,
                    Exhibit 4.1).

      4.17          AmerenUE company order dated August 22, 2002 establishing
                    the 5.25% Senior Secured Notes due 2012 (Form 8-K dated
                    August 22, 2002, Exhibit 4.2).

      4.18          AmerenUE company order dated March 10, 2003 establishing the
                    5.50% Senior Secured Notes due 2034 (Form 8-K dated March
                    10, 2003, Exhibit 4.2).

     10.1        *  Ameren Corporation (Ameren) Long-Term Incentive Plan of 1998
                    (Ameren' 1998 Form 10-K, Exhibit 10.1).

     10.2        *  Ameren Change of Control Severance Plan (Ameren's 1998 Form
                    10-K, Exhibit 10.2).

     10.3        *  Ameren Deferred Compensation Plan for Members of the Ameren
                    Leadership Team as amended and restated effective January 1,
                    2001 (Ameren's 2000 Form 10-K, Exhibit 10.1).

     10.4        *  Ameren Deferred Compensation Plan for Members of the Board
                    of Directors (Ameren's 1998 Form 10-K, Exhibit 10.4).

     10.5        *  Ameren Executive Incentive Compensation Program Elective
                    Deferral Provisions for Members of the Ameren Leadership
                    Team as amended and restated effective January 1, 2001
                    (Ameren's 2000 Form 10-K, Exhibit 10.2).

                                       3


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

     10.6           Amended Joint Dispatch Agreement among AmerenUE,
                    AmerenEnergy Generating Company (Generating Company) and
                    Central Illinois Public Service Company d/b/a AmerenCIPS
                    (File No. 333-56594, Exhibit 10.4).

     10.7           Power Sales Agreement between AmerenEnergy Marketing Company
                    (Marketing Company) and AmerenUE (September 30, 2001
                    Generating Company Form 10-Q, Exhibit 10.1).

     10.8           Power Sales Agreement between Marketing Company and AmerenUE
                    (March 31, 2002 Generating Company Form 10-Q, Exhibit 10.1).

     10.9           Lease Agreement dated as of December 1, 2002 between the
                    City of Bowling Green, Missouri, as Lessor, and AmerenUE, as
                    Lessee (2002 Form 10-K Exhibit 10.9).

     10.10          Trust Indenture dated as of December 1, 2002 between the
                    City of Bowling Green, Missouri and Commerce Bank, N.A. as
                    Trustee (2002 Form 10-K Exhibit 10.10).

     10.11          Bond Purchase Agreement dated as of December 20, 2002
                    between the City of Bowling Green, Missouri and AmerenUE as
                    purchaser (2002 Form 10-K Exhibit 10.11).

     10.12          Amended and Restated Appendix I ITC Agreement dated
                    February 14, 2003 between the Midwest Independent
                    Transmission System Operator, Inc. (Midwest ISO) and
                    GridAmerica LLC (GridAmerica) (Ameren 2002 Form 10-K,
                    Exhibit 10.17).

     10.13          Amended and Restated Limited Liability Company Agreement of
                    GridAmerica dated February 14, 2003 (Ameren 2002 Form 10-K,
                    Exhibit 10.18).

     10.14          Amended and Restated Master Agreement by and among
                    GridAmerica, GridAmerica Holdings Inc., GridAmerica
                    Companies and National Grid USA dated February 14, 2003
                    (Ameren 2002 Form 10-K, Exhibit 10.9).

     10.15          Amended and Restated Operation Agreement by and among
                    AmerenUE, Central Illinois Public Service Company d/b/a
                    AmerenCIPS, American Transmission Systems, Inc., Northern
                    Indiana Public Service Company and GridAmerica dated
                    February 14, 2003 (Ameren 2002 Form 10-K, Exhibit 10.10).

                                       4

         Exhibit No.                           Description
         ----------                            -----------
     12.1      **   Statement of Computation of Ratio of Earnings to Fixed
                    Charges and Preferred Stock Dividend Requirements.

     23.1           Consent of Independent Accountants (2002 Form 10-K
                    Exhibit 23.1)

     99.1           Stipulation and Agreement dated July 15, 2002 in Missouri
                    Public Service Commission (as No. EC-2002-1 (earnings
                    complaint case against AmerenUE) File Nos. 333-87506 and
                    333-87506-01, Exhibit 99.1).

     99.2           Certificate of Chief Executive Officer required by Section
                    906 of the Sarbanes-Oxley Act of 2002 (2002 Form 10-K
                    Exhibit 99.2).

     99.3           Certificate of Chief Financial Officer required by Section
                    906 of the Sarbanes-Oxley Act of 2002 (2002 Form 10-K
                    Exhibit 99.3).

     __________________
     * Management compensatory plan or arrangement
     ** Filed herewith.



                         Exhibits Available Upon Request
                         -------------------------------

     The  following  instrument  defining  the  rights  of  holders  of  certain
unregistered long-term debt of AmerenUE has not been filed with the SEC but will
be furnished upon request.

          -    Loan Agreement  dated as of March 1, 2000,  between  AmerenUE and
               the  State   Environmental   Improvement  and  Energy   Resources
               Authority of the State of Missouri (EIERA) in connection with the
               EIERA's $186,500,000  Environmental Improvement Revenue Refunding
               Bonds (AmerenUE Project)  ($63,500,000 Series 2000A,  $63,000,000
               Series 2000B, and $60,000,000 Series 2000C) due March 1, 2035.

Note:     Reports of Ameren  Corporation on Forms 8-K, 10-Q and 10-K are on file
          with the SEC under File Number 1-14756.

          Reports of Central  Illinois Public Service Company on Forms 8-K, 10-Q
          and 10-K are on file with the SEC under File Number 1-3672.

          Reports of AmerenEnergy Generating Company on Forms 8-K, 10-Q and 10-K
          are on file with the SEC under File Number 333-56594.

          Reports of CILCORP  Inc. on Forms 8-K,  10-Q and 10-K are on file with
          the SEC under File Number 1-8946.

          Reports of Central  Illinois Light Company on Forms 8-K, 10-Q and 10-K
          are on file with the SEC under File Number 1-2732.



                                       5




                                   SIGNATURES

     Pursuant  to the  requirements  of  Section  13 or 15(d) 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.

                                      UNION ELECTRIC COMPANY
                                            (Registrant)


                                          /s/ Martin J. Lyons
Date  March 31, 2003                  By -------------------------
                                              Martin J. Lyons
                                         Vice President and Controller
                                         (Principal Accounting Officer

                                 CERTIFICATIONS

     I, Charles W. Mueller, certify that:

     1. I have  reviewed  this annual  report on Form  10-K/A of Union  Electric
Company;

     2. Based on my  knowledge,  this annual  report does not contain any untrue
statement of a material fact or omit to state a material fact  necessary to make
the statements made, in light of the  circumstances  under which such statements
were made,  not  misleading  with  respect to the period  covered by this annual
report;

     3. Based on my knowledge,  the financial  statements,  and other  financial
information  included  in this annual  report,  fairly  present in all  material
respects the financial  condition,  results of operations  and cash flows of the
registrant as of, and for, the periods presented in this annual report;

     4. The  registrant's  other  certifying  officer and I are  responsible for
establishing and maintaining  disclosure  controls and procedures (as defined in
Exchange Act Rules 13a-14 and 15d-14) for the registrant and have:

          a)   designed such  disclosure  controls and procedures to ensure that
               material  information  relating to the registrant,  including its
               consolidated  subsidiaries,  is made known to us by others within
               those  entities,  particularly  during  the  period in which this
               annual report is being prepared;

          b)   evaluated  the  effectiveness  of  the  registrant's   disclosure
               controls and  procedures as of a date within 90 days prior to the
               filing date of this annual report (the "Evaluation Date"); and

          c)   presented  in  this  annual  report  our  conclusions  about  the
               effectiveness of the disclosure  controls and procedures based on
               our evaluation as of the Evaluation Date;

     5. The registrant's other certifying officer and I have disclosed, based on
our most recent evaluation, to the registrant's auditors and the audit committee
of  registrant's  board of  directors  (or  persons  performing  the  equivalent
functions):

          a)   all  significant  deficiencies  in the  design  or  operation  of
               internal  controls which could adversely  affect the registrant's
               ability to record,  process,  summarize and report financial data
               and have  identified for the  registrant's  auditors any material
               weaknesses in internal controls; and

          b)   any fraud,  whether or not material,  that involves management or
               other employees who have a significant  role in the  registrant's
               internal controls; and

     6. The registrant's other certifying  officers and I have indicated in this
annual report whether there were significant  changes in internal controls or in
other factors that could  significantly  affect internal controls  subsequent to
the date of our most recent  evaluation,  including any corrective  actions with
regard to significant deficiencies and material weaknesses.


Date: March 31, 2003                          /s/ Charles W. Mueller
                                           -----------------------------
                                                  Charles W. Mueller
                                                 Chief Executive Officer



                                       6


     I, Warner L. Baxter, certify that:

     1. I have  reviewed  this annual  report on Form  10-K/A of Union  Electric
Company;

     2. Based on my  knowledge,  this annual  report does not contain any untrue
statement of a material fact or omit to state a material fact  necessary to make
the statements made, in light of the  circumstances  under which such statements
were made,  not  misleading  with  respect to the period  covered by this annual
report;

     3. Based on my knowledge,  the financial  statements,  and other  financial
information  included  in this annual  report,  fairly  present in all  material
respects the financial  condition,  results of operations  and cash flows of the
registrant as of, and for, the periods presented in this annual report;

     4. The  registrant's  other  certifying  officer and I are  responsible for
establishing and maintaining  disclosure  controls and procedures (as defined in
Exchange Act Rules 13a-14 and 15d-14) for the registrant and have:

          a)   designed such  disclosure  controls and procedures to ensure that
               material  information  relating to the registrant,  including its
               consolidated  subsidiaries,  is made known to us by others within
               those  entities,  particularly  during  the  period in which this
               annual report is being prepared;

          b)   evaluated  the  effectiveness  of  the  registrant's   disclosure
               controls and  procedures as of a date within 90 days prior to the
               filing date of this annual report (the "Evaluation Date"); and

          c)   presented  in  this  annual  report  our  conclusions  about  the
               effectiveness of the disclosure  controls and procedures based on
               our evaluation as of the Evaluation Date;

     5. The registrant's other certifying officer and I have disclosed, based on
our most recent evaluation, to the registrant's auditors and the audit committee
of  registrant's  board of  directors  (or  persons  performing  the  equivalent
functions):

          a)   all  significant  deficiencies  in the  design  or  operation  of
               internal  controls which could adversely  affect the registrant's
               ability to record,  process,  summarize and report financial data
               and have  identified for the  registrant's  auditors any material
               weaknesses in internal controls; and

          b)   any fraud,  whether or not material,  that involves management or
               other employees who have a significant  role in the  registrant's
               internal controls; and

     6. The registrant's  other certifying  officer and I have indicated in this
annual report whether there were significant  changes in internal controls or in
other factors that could  significantly  affect internal controls  subsequent to
the date of our most recent  evaluation,  including any corrective  actions with
regard to significant deficiencies and material weaknesses.



Date: March 31, 2003                          /s/ Warner L. Baxter
                                           -----------------------------
                                                  Warner L. Baxter
                                                 Chief Financial Officer
                                       7




                                                                  Exhibit 12.1




                             UNION ELECTRIC COMPANY
COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES AND PREFERRED STOCK DIVIDEND REQUIREMENTS
                      (Millions of Dollars, Except Ratios)


                                                        Year Ended December 31,

                                                 --------------------------------- -----
                                                  1998    1999     2000    2001     2002

                                                                    
Net Income                                        $320    $349     $353    $374    $344
Add- Extraordinary items net of tax                  -       -        -       5       -
                                                 -----   -----    -----   -----   -----
Net income from continuing operations              320     349      353     379     344

   Taxes based on income                           213     227      224     230     193
                                                 -----   -----    -----   -----   -----
Net income before income taxes                     533     576      577     609     537


Add- fixed charges:
   Interest on long term debt                      125     118      122     109      98
   Other interest                                    2      (1)       4       4       7
   Rentals                                           3       4        4       4       3
   Amortization of net debt premium,
    discount, expenses and losses                    4       3        3       3       3

                                                 -----   -----    -----   -----   -----
Total fixed charges                                134     124      133     120     111
                                                 -----   -----    -----   -----   -----

Earnings available for fixed charges               667     700      710     729     648
                                                 =====   =====    =====   =====   =====

Ratio of earnings to fixed charges                4.99    5.64     5.33    6.08    5.82
                                                 =====   =====    =====   =====   =====

Earnings required for preferred dividends:
   Preferred stock dividends                         9       9        9       9       8
   Adjustment to pre-tax basis                       5       4        4       4       3
                                                 -----   -----    -----   -----   -----
                                                    14      13       13      13      11

Fixed charges plus preferred stock dividend
    requirements                                   148     137      146     133     122
                                                 =====   =====    =====   =====   =====

Ratio of earnings to fixed charges plus
    preferred stock dividend requirements         4.53    5.09     4.85    5.48    5.30
                                                 =====   =====    =====   =====   =====




                                       8