UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549


                                    FORM 10-Q

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

         For The Quarterly Period Ended March 31, 2003

[  ]     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 1-3672

                     CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
             (Exact name of registrant as specified in its charter)


                     Illinois                                   37-0211380
         (State or other jurisdiction of                     (I.R.S. Employer
         incorporation or organization)                      Identification No.)



               607 East Adams Street, Springfield, Illinois 62739
              (Address of principal executive offices and Zip Code)

                         Registrant's telephone number,
                       including area code: (217) 523-3600


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

     Shares  outstanding  of the  registrant's  common stock as of May 14, 2003:
Common Stock, no par value,  held by Ameren  Corporation  (parent company of the
registrant) - 25,452,373.

<PAGE>


                     CENTRAL ILLINOIS PUBLIC SERVICE COMPANY

                                TABLE OF CONTENTS
                                                                           Page

PART I.      Financial Information

   ITEM 1.   Financial Statements (Unaudited)
             Balance Sheet at March 31, 2003 and December 31, 2002........... 2
             Statement of Income for the three months ended March 31, 2003
             and 2002........................................................ 3
             Statement of Cash Flows for the three months ended March 31,
             2003 and 2002................................................... 4
             Statement of Common Stockholder's Equity for the three months
             ended March 31, 2003 and 2002................................... 5
             Notes to Financial Statements................................... 6

   ITEM 2.   Management's Discussion and Analysis of Financial Condition
             and Results of Operations....................................... 12

   ITEM 3.   Quantitative and Qualitative Disclosures About Market Risk...... 20

   ITEM 4.   Controls and Procedures......................................... 21

PART II.     Other Information

   ITEM 1.   Legal Proceedings............................................... 23

   ITEM 6.   Exhibits and Reports on Form 8-K................................ 23

SIGNATURE.................................................................... 24

CERTIFICATIONS............................................................... 24

This Form 10-Q  contains  "forward-looking  statements"  within  the  meaning of
Section 21E of the Securities Exchange Act of 1934.  Forward-looking  statements
should be read with the cautionary  statements and important factors included in
this Form 10-Q at Part I,  Item 2.  "Management's  Discussion  and  Analysis  of
Financial   Condition   and   Results   of   Operations,"   under  the   heading
"Forward-Looking  Statements."  Forward-looking  statements  are all  statements
other than statements of historical  fact,  including those  statements that are
identified  by the  use  of the  words  "anticipates,"  "estimates,"  "expects,"
"intends," "plans," "predicts," "projects," and similar expressions.


                                       1

<PAGE>
<TABLE>
<CAPTION>
                                 PART I. FINANCIAL INFORMATION

ITEM 1.  Financial Statements.

                            CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
                                         BALANCE SHEET
                                   (Unaudited, in millions)

                                                                                 March 31,     December 31,
                                                                                    2003            2002
                                                                                -----------    ------------
<S>                                                                              <C>             <C>
ASSETS:
Property and plant, net                                                           $   822         $   825
Investments and other assets:
   Intercompany notes receivable - Generating Company                                 373             373
   Intercompany tax receivable - Generating Company                                   159             162
   Other assets                                                                        18              17
                                                                                  -------         -------

         Total investments and other assets                                           550             552
                                                                                  -------         -------

Current assets:
   Cash and cash equivalents                                                           16              17
   Accounts receivable - trade (less allowance for doubtful
         accounts of $2 and $1, respectively)                                          64              53
   Unbilled revenue                                                                    57              74
   Intercompany notes receivable                                                       23              16
   Miscellaneous accounts and notes receivable                                         27              22
   Current portion of intercompany notes receivable - Generating Company               46              46
   Current portion of intercompany tax receivable - Generating Company                 13              13
   Materials and supplies, at average cost                                             19              41
   Other current assets                                                                 6               7
                                                                                  -------         -------
         Total current assets                                                         271             289
                                                                                  -------         -------

Regulatory assets                                                                      30              31
                                                                                  -------         -------
Total Assets                                                                      $ 1,673         $ 1,697
                                                                                  =======         =======

CAPITAL AND LIABILITIES:
Capitalization:
   Common stock, no par value, 45.0 shares authorized -
     25.5 shares outstanding                                                      $   120         $   120
   Retained earnings                                                                  387             405
   Accumulated other comprehensive income                                             (13)            (13)
                                                                                  -------         -------

      Total common stockholder's equity                                               494             512
                                                                                  -------         -------

   Preferred stock not subject to mandatory redemption                                 80              80
   Long-term debt, net                                                                534             534
                                                                                  -------         -------

         Total capitalization                                                       1,108           1,126
                                                                                  -------         -------

Current liabilities:
   Current maturities of long-term debt                                                40              45
   Accounts and wages payable                                                          77              87
   Taxes accrued                                                                       38              32
   Other current liabilities                                                           31              26
                                                                                  -------         -------

         Total current liabilities                                                    186             190
                                                                                  -------         -------

Accumulated deferred income taxes                                                     277             282
Accumulated deferred investment tax credits                                            12              13
Regulatory liabilities                                                                 15              15
Other deferred credits and liabilities                                                 75              71
                                                                                  -------         -------

Total Capital and Liabilities                                                     $ 1,673         $ 1,697
                                                                                  =======         =======

See Notes to Financial Statements.
</TABLE>

                                       2

<PAGE>

<TABLE>
<CAPTION>

             CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
                       STATEMENT OF INCOME
                    (Unaudited, in millions)


                                                            Three Months Ended
                                                                 March 31,
                                                            -------------------
                                                               2003      2002
                                                            --------   --------
<S>                                                           <C>      <C>
OPERATING REVENUES:
   Electric                                                    $ 132    $ 150
   Gas                                                            77       65
                                                               -----    -----
    Total operating revenues                                     209      215
                                                               -----    -----

OPERATING EXPENSES:
   Purchased power                                                86      105
   Gas                                                            53       44
   Other operations and maintenance                               42       41
   Depreciation and amortization                                  13       12
   Income taxes                                                   (1)       1
   Other taxes                                                     9        9
                                                               -----    -----
      Total operating expenses                                   202      212
                                                               -----    -----

OPERATING INCOME                                                   7        3

OTHER INCOME AND (DEDUCTIONS):
   Miscellaneous, net -
     Miscellaneous income                                          7       10
     Miscellaneous expense                                        (1)      (1)
     Income taxes                                                 (2)       -
                                                               -----    -----
      Total other income and (deductions)                          4        9
                                                               -----    -----

INTEREST CHARGES                                                   9       10
                                                               -----    -----

NET INCOME                                                         2        2

PREFERRED STOCK DIVIDENDS                                          1        1
                                                               -----    -----

NET INCOME AFTER PREFERRED STOCK DIVIDENDS                     $   1    $   1
                                                               =====    =====

See Notes to Financial Statements.
</TABLE>


                                       3
<PAGE>
<TABLE>
<CAPTION>

                     CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
                             STATEMENT OF CASH FLOWS
                            (Unaudited, in millions)

                                                             Three Months Ended
                                                                  March 31,
                                                             ------------------
                                                                2003     2002
                                                               ------   ------
<S>                                                            <C>      <C>
Cash Flows From Operating:
   Net income                                                   $  2     $  2
   Adjustments to reconcile net income to net cash
       provided by operating activities:
         Depreciation and amortization                            13       12
         Deferred income taxes, net                               (5)      (5)
         Deferred investment tax credits, net                     (1)       -
         Changes in assets and liabilities:
               Receivables, net                                    1        5
               Materials and supplies                             22       18
               Accounts and wages payable                        (10)     (42)
               Taxes accrued                                       6        6
               Assets, other                                       4        9
               Liabilities, other                                  9        6
                                                                ----     ----
Net cash provided by operating activities                         41       11
                                                                ----     ----
Cash Flows From Investing:
   Construction expenditures                                     (10)     (12)
   Intercompany notes receivable                                  (7)      18
                                                                ----     ----
Net cash (used in)/provided by investing activities              (17)       6
                                                                ----     ----

Cash Flows From Financing:
   Dividends on common stock                                     (19)     (15)
   Dividends on preferred stock                                   (1)      (1)
   Redemptions:
      Long-term debt                                              (5)      (5)
                                                                ----     ----
Net cash used in financing activities                            (25)     (21)
                                                                ----     ----

Net change in cash and cash equivalents                           (1)      (4)
Cash and cash equivalents at beginning of year                    17       26
                                                                ----     ----
Cash and cash equivalents at end of period                      $ 16     $ 22
                                                                ====     ====

Cash paid during the periods:
   Interest                                                      $ 5     $  6
   Income taxes, net                                               -        -

See Notes to Financial Statements.


</TABLE>

                                       4

<PAGE>
<TABLE>
<CAPTION>

                     CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
                    STATEMENT OF COMMON STOCKHOLDER'S EQUITY
                            (Unaudited, in millions)



                                                             Three Months Ended
                                                                  March 31,
                                                             ------------------
                                                                2003     2002
                                                                -----    -----
<S>                                                            <C>      <C>
Common stock                                                    $ 120    $ 120

Retained earnings
   Beginning balance                                              405      444
   Net income                                                       2        2
   Common stock dividends                                         (19)     (15)
   Preferred stock dividends                                       (1)      (1)
                                                                -----    -----
                                                                  387      430
                                                                -----    -----

Accumulated other comprehensive income
   Beginning balance - minimum pension liability                  (13)       -
   Change in minimum pension liability in current
      period                                                        -        -
                                                                -----    -----
                                                                  (13)       -
                                                                -----    -----

Total common stockholder's equity                               $ 494    $ 550
                                                                =====    =====


See Notes to Financial Statements.
</TABLE>


                                       5
<PAGE>

CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
NOTES TO FINANCIAL STATEMENTS (UNAUDITED)
March 31, 2003


NOTE 1 - Summary of Significant Accounting Policies

General

     Central  Illinois  Public Service  Company,  headquartered  in Springfield,
Illinois,  operates as  AmerenCIPS  and is a  wholly-owned  subsidiary of Ameren
Corporation (Ameren). Our principal business is the rate-regulated  transmission
and  distribution  of  electricity  and  the  distribution  of  natural  gas  to
residential, commercial, industrial and wholesale users in Illinois. Ameren is a
public  utility  holding  company  registered  with the  Securities and Exchange
Commission  (SEC) under the Public Utility  Holding  Company Act of 1935 (PUHCA)
and is headquartered in St. Louis, Missouri.  Ameren' principal business is the
generation, transmission and distribution of electricity and the distribution of
natural gas to  residential,  commercial,  industrial and wholesale users in the
central United States. In addition to us, Ameren's primary  subsidiaries and our
affiliates are as follows:

o    Union  Electric   Company,   which  operates  a   rate-regulated   electric
     generation,  transmission and distribution  business,  and a rate-regulated
     natural gas distribution business in Missouri and Illinois as AmerenUE.
o    Central  Illinois  Light Company,  a subsidiary of CILCORP Inc.  (CILCORP),
     which operates a rate-regulated  transmission and distribution business, an
     electric generation business and a rate-regulated  natural gas distribution
     business in Illinois as  AmerenCILCO.  Ameren  completed its acquisition of
     CILCORP on January 31, 2003.
o    AmerenEnergy  Resources Company (Resources Company),  which consists of non
     rate-regulated  operations.  Subsidiaries include  AmerenEnergy  Generating
     Company  (Generating  Company),  which operates Ameren's non rate-regulated
     electric  generation  in  Missouri  and  Illinois,  AmerenEnergy  Marketing
     Company (Marketing Company), which markets power for periods over one year,
     AmerenEnergy  Fuels and Services  Company,  which procures fuel and manages
     the related risks for  Ameren-affiliated  companies and AmerenEnergy Medina
     Valley Cogen (No. 4), LLC, which  indirectly owns a 40 megawatt,  gas-fired
     electric  generation  plant.  On February  4, 2003,  Ameren  completed  its
     acquisition  of AES Medina  Valley Cogen (No.  4), LLC (Medina  Valley) and
     renamed it  AmerenEnergy  Medina  Valley  Cogen (No.  4),  LLC.  Generating
     Company  supplies  electric  power to  Marketing  Company  which,  in turn,
     supplies  us with  power  under  a power  supply  agreement  (Power  Supply
     Agreement).
o    AmerenEnergy,  Inc.  (AmerenEnergy),  which serves as a power marketing and
     risk management agent for  Ameren-affiliated  companies for transactions of
     primarily less than one year.
o    Electric  Energy,  Inc.  (EEI),  which  operates  electric  generation  and
     transmission facilities in Illinois. Ameren has a 60% ownership interest in
     EEI, 40% owned by AmerenUE and 20% owned by Resources Company.
o    Ameren Services  Company (Ameren  Services),  which provides shared support
     services to Ameren and its  subsidiaries,  including us.  Charges are based
     upon the actual  costs  incurred  by Ameren  Services,  as  required by the
     PUHCA.

     When we refer to  AmerenCIPS,  our, we or us, we are  referring  to Central
Illinois  Public  Service  Company.  All tabular dollar amounts are in millions,
unless otherwise indicated.

     Our accounting policies conform to generally accepted accounting principles
in the United States (GAAP).  Our financial  statements  reflect all adjustments
(which include normal,  recurring adjustments)  necessary, in our opinion, for a
fair  presentation of our interim results.  These  statements  should be read in
conjunction with the financial statements and notes thereto included in our 2002
Annual Report on Form 10-K.


                                       6

<PAGE>

     The  preparation of financial  statements in conformity  with GAAP requires
management  to make  certain  estimates  and  assumptions.  Such  estimates  and
assumptions  affect reported amounts of assets and liabilities and disclosure of
contingent  assets and  liabilities at the date of the financial  statements and
the reported amounts of revenues and expenses during the reported period. Actual
results could differ from those estimates.  Certain  reclassifications have been
made to prior years' financial statements to conform to 2003 reporting.

Accounting Changes and Other Matters

Statement of Financial  Accounting  Standards  (SFAS) No. 143 - "Accounting  for
Asset Retirement Obligations"

     We adopted the provisions of SFAS 143 on January 1, 2003. SFAS 143 provides
the accounting  requirements  for asset retirement  obligations  associated with
tangible,  long-lived assets.  SFAS 143 requires us to record the estimated fair
value of legal obligations associated with the retirement of tangible long-lived
assets in the period in which the  liabilities  are incurred and to capitalize a
corresponding  amount as part of the book value of the related long-lived asset.
In subsequent  periods,  we are required to adjust asset retirement  obligations
based on changes in estimated  fair value,  and the  corresponding  increases in
asset book values are  depreciated  over the useful  life of the related  asset.
Uncertainties  as to the  probability,  timing or cash flows  associated with an
asset retirement obligation affect our estimate of fair value.

     We  have  determined  that  certain  asset  retirement  obligations  exist.
However,  we are unable to estimate the fair value of those obligations  because
the  probability,  timing or cash  flows  associated  with the  obligations  are
indeterminable.  We do not believe that these obligations,  when incurred,  will
have a material adverse impact on our financial position,  results of operations
or liquidity.

     Historically,  we  have  included  an  estimated  cost of  dismantling  and
removing plant from service upon  retirement.  Because these  estimated costs of
removal have been included in the cost of service upon which our present utility
rates are based,  and with the  expectation  that this practice will continue in
the  jurisdictions  in which we operate,  adoption of SFAS 143 did not result in
any  change  in the  depreciation  accounting  practices  of our  rate-regulated
operations.  We have  estimated  future  removal costs  embedded in  accumulated
depreciation  related to  rate-regulated  plant assets were  approximately  $126
million at March 31, 2003.


FASB  Interpretation  No.  (FIN) 45 -  "Guarantor's  Accounting  and  Disclosure
Requirements for Guarantees,  Including  Indirect  Guarantees of Indebtedness of
Others"

     FIN 45 was issued in  November  2002 and  requires  that upon  issuance  of
certain guarantees, a guarantor must recognize a liability for the fair value of
the obligation assumed under the guarantee.  These recognition provisions of FIN
45 are to be applied on a  prospective  basis to  guarantees  issued or modified
after December 31, 2002, irrespective of the guarantor's fiscal year-end. FIN 45
also requires  additional  disclosures  by a guarantor in its interim and annual
financial  statements for periods ending after December 15, 2002.  Because we do
not have such obligations, the recognition provisions of FIN 45 did not have any
effect on our  financial  position,  results of  operations  or liquidity in the
first quarter of 2003.

Revenue

     We accrue an estimate of electric and gas  revenues  for service  rendered,
but unbilled, at the end of each accounting period.

     Interchange  revenues  included in  Operating  Revenues - Electric  were $8
million for the three months ended March 31, 2003 (2002 - $10 million).

                                       7
<PAGE>


Purchased Power

     Purchased  power included in Operating  Expenses - Purchased  Power was $86
million for the three months ended March 31, 2003 (2002 - $105 million).

Excise Taxes

     Excise taxes on our  Illinois gas customer  bills are imposed on us and are
recorded gross in Operating  Revenues and Other Taxes.  Excise taxes recorded in
Operating  Revenues  and Other Taxes for the three  months  ended March 31, 2003
were $5  million  (2002 - $5  million).  Excise  taxes  applicable  to  Illinois
electric  customer  bills are imposed on the  consumer  and are  recorded as tax
collections payable and included in Taxes Accrued on the Balance Sheet.


NOTE 2 - Rate and Regulatory Matters

Regional Transmission Organization

     Since  April  2002,  we  and  AmerenUE  and   subsidiaries  of  FirstEnergy
Corporation  and NiSource Inc.  (collectively  the  GridAmerica  Companies) have
participated in a number of filings at the Federal Energy Regulatory  Commission
(FERC) in an  effort  to form  GridAmerica  LLC as an  independent  transmission
company  (ITC).  On December  19, 2002,  the FERC issued an order  conditionally
approving  the  formation  and  operation  of  GridAmerica  as an ITC within the
Midwest Independent System Operator (Midwest ISO), subject to further compliance
filings.

     In response to the December 19, 2002 order, the GridAmerica  Companies made
three  additional  filings at the FERC.  On  January  31,  2003 the  GridAmerica
Companies filed a request for  authorization to transfer  functional  control of
certain   transmission  assets  to  GridAmerica.   On  February  18,  2003,  the
GridAmerica  Companies  filed  revised  agreements  codifying  the formation and
operation  of  GridAmerica  to  reflect  changes  requested  by the  FERC in the
December  19, 2002 order.  On  February  28,  2003,  the  GridAmerica  Companies
together  with the  Midwest ISO filed  revisions  to the Midwest ISO Open Access
Transmission  Tariff (OATT) to provide  rates for service over the  transmission
facilities to be transferred to GridAmerica by the GridAmerica Companies.

     On April 30 2003,  the FERC  issued  orders in  response to the January 31,
2003 and February  28, 2003  filings.  In its order  regarding  the  GridAmerica
Companies' request to transfer  functional control of their transmission  assets
to GridAmerica,  the FERC  authorized the transfer.  In response to the February
28,  2003  filing,  the FERC  accepted  the  amendments  to the Midwest ISO OATT
effective upon the  commencement  of service over the  GridAmerica  transmission
facilities  under the  Midwest  ISO OATT,  suspended  the  proposed  rates for a
nominal period,  subject to refund, and established hearing and settlement judge
procedures  to determine  the justness and  reasonableness  of the proposed rate
amendments  to the Midwest ISO OATT.  An order in response to the  February  18,
2003 filing is still pending.

     Until  the  tariffs  and  other   material  terms  of  our  and  AmerenUE's
participation  in GridAmerica,  and  GridAmerica's  participation in the Midwest
ISO, are finalized and approved by the FERC, we are unable to predict the impact
that on-going regional transmission  organization  developments will have on our
financial position, results of operations or liquidity. AmerenUE's participation
in  GridAmerica  is  subject  to  Missouri  Public  Service  Commission  (MoPSC)
approval. An order from the MoPSC is expected during 2003.

Standard Market Design Notice of Proposed Rulemaking (NOPR)

     On July 31, 2002,  the FERC issued a Standard  Market Design NOPR. The NOPR
proposes  a number of  changes  to the way the  current  wholesale  transmission
service and energy  markets are operated.  Specifically,  the NOPR calls for all
jurisdictional  transmission  facilities  to be placed  under the  control of an
independent   transmission   provider  (similar  to  an  RTO),  proposes  a  new
transmission  service tariff that provides a single form of transmission service
for all users of the  transmission  system  including  bundled


                                       8
<PAGE>

retail load, and proposes a new energy market and congestion  management  system
that uses  locational  marginal  pricing as its basis.  On November 15, 2002, we
filed our initial comments on the NOPR with the FERC expressing concern with the
potential  impact of the  proposed  rules in their  current form on the cost and
reliability  of service  to retail  customers.  We also  proposed  that  certain
modifications  be made to the  proposed  rules in order to protect  transmission
owners  from the  possibility  of trapped  transmission  costs that might not be
recoverable from ratepayers as a result of inconsistent  regulatory policies. We
filed additional comments on the remaining sections of the NOPR during the first
quarter of 2003.

     On April  28,  2003 the FERC  issued a "white  paper"  reflecting  comments
received in response to the NOPR. More  specifically,  the white paper indicated
that the FERC will not assert  jurisdiction over the transmission rate component
of bundled retail service and will insure that existing bundled retail customers
retain  their  existing  transmission  rights and retain  rights for future load
growth in its final rule. Moreover,  the white paper acknowledged that the final
rule will  provide  the states  with input on  resource  adequacy  requirements,
allocation of firm transmission rights, and transmission planning. The FERC also
requested   input  on  the   flexibility   and   timing  of  the  final   rule's
implementation.

     Even though issuance of the final rule and its implementation  schedule are
still  unknown,  the  Midwest ISO is already in the  process of  implementing  a
market design similar to the proposed market design in the NOPR. The Midwest ISO
has  targeted  March  2004 as the start date for  implementation.  We are in the
process of reviewing the FERC's white paper. Until the FERC issues a final rule,
we and Ameren are unable to predict the ultimate impact on our future  financial
position, results of operations or liquidity.

Illinois Gas

     In November 2002, we filed a request with the Illinois Commerce  Commission
(ICC) to increase  annual  rates for natural  gas service by  approximately  $16
million.  The ICC has until  October 2003 to render a decision on this  request;
however,  the ICC Staff has recommended an annual increase of  approximately  $8
million.

Illinois Electric

     In  2002,  all of  our  Illinois  residential,  commercial  and  industrial
customers had choice in electric  suppliers as provided by the Electric  Service
Customer Choice and Rate Relief Law of 1997.  Several  commercial and industrial
customers  switched to Marketing  Company for their energy supply resulting in a
decline in our  revenues  and a  corresponding  decrease in  purchased  power of
approximately  $19 million for the first  quarter of 2003.  We continue to incur
delivery  service  costs  and  charge  related  tariffs  associated  with  these
customers.


NOTE 3 - Related Party Transactions

     We have  transactions  in the normal course of business with Ameren and its
other  subsidiaries.   These  transactions  are  primarily  comprised  of  power
purchases  and  sales,   as  well  as  other  services   received  or  rendered.
Intercompany  power purchases under the Power Supply  Agreement and from EEI, an
affiliate, totaled $86 million for the three months ended March 31, 2003 (2002 -
$105 million).

     We have the ability to borrow from Ameren and  AmerenUE,  through a utility
money pool  agreement.  Ameren  Services  administers the utility money pool and
tracks internal and external funds separately.  Internal funds are surplus funds
contributed to the money pool from participants.  The primary source of external
funds for the  utility  money pool at March 31, 2003 was  AmerenUE's  commercial
paper program.  Through the utility money pool, we can access  committed  credit
facilities at Ameren and AmerenUE, which totaled $679 million at March 31, 2003.
These  facilities  are in addition to our own $15  million in  committed  credit
facilities.  The total amount available to us at any given time from the utility
money  pool is  reduced  by the  amount of  borrowings  by our  affiliates,  but
increased to the extent Ameren,  AmerenUE or Ameren  Services have surplus funds
and  the  availability  of  other  external  borrowing  sources.  Surplus  funds
providing  additional  liquidity  available to us through the utility money pool
totaled  $260  million  at March 31,  2003.  The  availability  of funds is also
determined by funding  requirements  and limits  established  by the PUHCA.  We,
along with  AmerenUE  and Ameren  Services,  rely on the  utility  money


                                       9

<PAGE>

pool to coordinate and provide for certain  short-term  cash and working capital
requirements.  Borrowers receiving a loan under the utility money pool agreement
must repay the principal  amount of such loan,  together with accrued  interest.
Interest is calculated at varying rates of interest depending on the composition
of internal and external funds in the utility money pool.  The average  interest
rate for the utility  money pool for the three  months  ended March 31, 2003 was
1.32% (2002 - 1.79%).  At March 31,  2003,  we had $23  million in  intercompany
receivables  outstanding  (December 31, 2002 - $16 million)  through the utility
money pool.

     On April 1, 2003,  AmerenUE  entered into an additional  364-day  committed
credit facility totaling $75 million to be used for general corporate  purposes,
including  support of commercial paper programs.  This facility makes borrowings
available  at various  interest  rates  based on LIBOR,  agreed  rates and other
options. We and Ameren can access this facility through the utility money pool.

     Support  services  provided by Ameren Services,  including wages,  employee
benefits and professional  services, are based on actual costs incurred. For the
three months ended March 31, 2003,  support services provided by Ameren Services
included in Operating  Expenses - Other  Operations and Maintenance  totaled $15
million (2002 - $16 million).

     As of March 31, 2003,  intercompany  receivables  included in Miscellaneous
Accounts and Notes Receivable were  approximately $20 million (December 31, 2002
- $12 million). As of March 31, 2003, intercompany payables included in Accounts
and Wages Payables totaled approximately $53 million (2002 - $63 million).

     Our  intercompany  interest  income  recorded in  Miscellaneous  Income was
approximately  $7 million for the three  months  ended March 31, 2003 (2002 - $8
million).


NOTE 4 - Property and Plant, Net
<TABLE>
<CAPTION>
Property and plant, net at March 31, 2003 and December 31, 2002, consisted of the following:

----------------------------------------------------------------------------------------------
                                                          March 31, 2003    December 31, 2002
----------------------------------------------------------------------------------------------
<S><C>                                                       <C>               <C>
Property and plant, at original cost:
  Electric                                                    $1,255            $1,248
  Gas                                                            291               290
  Other                                                            5                 5
----------------------------------------------------------------------------------------------
                                                              $1,551            $1,543
    Less accumulated depreciation and amortization               742               732
----------------------------------------------------------------------------------------------
                                                                 809               811
Construction work in progress:
  Other                                                           13                14
----------------------------------------------------------------------------------------------
Property and plant, net                                       $  822            $  825
----------------------------------------------------------------------------------------------
</TABLE>


NOTE 5 - Debt Financings

     On April 7, 2003, we redeemed,  with cash, prior to maturity and at par our
$50 million first mortgage bonds 7.5% Series X due July 1, 2007.

     At March 31, 2003, neither Ameren,  nor any of its subsidiaries,  including
us, had any  off-balance  sheet  financing  arrangements,  other than  operating
leases entered into in the ordinary course of business.  At this time, we do not
expect to engage in any significant off-balance sheet financing arrangements.

     Amortization  of debt issuance costs and any premium or discounts were less
than $1 million for the three  months  ended March 31, 2003 (2002 - less than $1
million) and were included in interest expense in the income statement.


                                       10

<PAGE>


     At March 31,  2003,  Ameren and its  subsidiaries,  including  us,  were in
compliance with financial agreement provisions and covenants.


NOTE 6 - Miscellaneous, Net

     Miscellaneous,  net for the three  months  ended  March  31,  2003 and 2002
consisted of the following:

--------------------------------------------------------------------------------
                                                         Three Months
                                                      2003          2002
--------------------------------------------------------------------------------
Miscellaneous income:
   Interest and dividend income                       $7             $8
   Equity in earnings of subsidiary                    -              1
   Other                                               -              1
--------------------------------------------------------------------------------
Total miscellaneous income                            $7            $10
--------------------------------------------------------------------------------

Miscellaneous expense:
   Other                                             $(1)           $(1)
--------------------------------------------------------------------------------
Total miscellaneous expense                          $(1)           $(1)
--------------------------------------------------------------------------------


NOTE 7 - Segment Information

     Our  business  segments  provide  electric  and gas  service in portions of
Illinois.  The  accounting  policies  of the  segments  are the  same  as  those
described in Note 1 - Summary of Significant  Accounting Policies.  Segment data
includes a charge allocating costs of administrative support services to each of
the  segments.  These costs are  accumulated  in a separate  Ameren  subsidiary,
Ameren Services, which provides a variety of support services to us. We evaluate
the  performance  of our  segments  and  allocate  resources  to them,  based on
revenues and operating income.

     Segment  information for the three months ended March 31, 2003 and 2002 was
as follows:

--------------------------------------------------------------------------------
                                        Electric           Gas          Total
--------------------------------------------------------------------------------
Three months ended March 31, 2003
--------------------------------------------------------------------------------
Revenues                                 $  132          $  77        $  209
Operating income                              3              4             7
--------------------------------------------------------------------------------
Three months ended March 31, 2002
--------------------------------------------------------------------------------
Revenues                                 $  150         $   65        $  215
Operating income/(loss)                      (1)             4             3
--------------------------------------------------------------------------------

                                       11

<PAGE>

ITEM 2. Management's  Discussion and Analysis of Financial Condition and Results
        of Operations.

OVERVIEW

     Central  Illinois  Public Service  Company,  headquartered  in Springfield,
Illinois,  operates as  AmerenCIPS  and is a  wholly-owned  subsidiary of Ameren
Corporation (Ameren). Our principal business is the rate-regulated  transmission
and  distribution  of  electricity  and  the  distribution  of  natural  gas  to
residential, commercial, industrial and wholesale users in Illinois. Ameren is a
public  utility  holding  company  registered  with the  Securities and Exchange
Commission  (SEC) under the Public Utility  Holding  Company Act of 1935 (PUHCA)
and is headquartered in St. Louis, Missouri.  Ameren's principal business is the
generation, transmission and distribution of electricity and the distribution of
natural gas to  residential,  commercial,  industrial and wholesale users in the
central United States. In addition to us, Ameren's primary  subsidiaries and our
affiliates are as follows:

o    Union  Electric   Company,   which  operates  a   rate-regulated   electric
     generation,  transmission and distribution  business,  and a rate-regulated
     natural gas distribution business in Missouri and Illinois as AmerenUE.
o    Central  Illinois  Light Company,  a subsidiary of CILCORP Inc.  (CILCORP),
     which operates a rate-regulated  transmission and distribution business, an
     electric generation business and a rate-regulated  natural gas distribution
     business in Illinois as  AmerenCILCO.  Ameren  completed its acquisition of
     CILCORP  on  January  31,  2003.  See  Recent   Developments   for  further
     information.
o    AmerenEnergy  Resources Company (Resources Company),  which consists of non
     rate-regulated  operations.  Subsidiaries include  AmerenEnergy  Generating
     Company (Generating  Company),  which operates non rate-regulated  electric
     generation  in  Missouri  and  Illinois,   AmerenEnergy  Marketing  Company
     (Marketing  Company),  which  markets  power  for  periods  over one  year,
     AmerenEnergy  Fuels and Services  Company,  which procures fuel and manages
     the related risks for  Ameren-affiliated  companies and AmerenEnergy Medina
     Valley Cogen (No.4),  LLC, which  indirectly owns a 40 megawatt,  gas-fired
     electric  co-generation  plant. On February 4, 2003,  Ameren  completed its
     acquisition  of AES Medina  Valley Cogen (No.  4), LLC (Medina  Valley) and
     renamed it  AmerenEnergy  Medina  Valley  Cogen (No.  4),  LLC.  See Recent
     Developments for further information.  Generating Company supplies electric
     power to Marketing  Company which, in turn,  supplies us with power under a
     power supply agreement (Power Supply Agreement).
o    AmerenEnergy,  Inc.  (AmerenEnergy),  which serves as a power marketing and
     risk management agent for  Ameren-affiliated  companies for transactions of
     primarily less than one year.
o    Electric  Energy,  Inc.  (EEI),  which  operates  electric  generation  and
     transmission facilities in Illinois. Ameren has a 60% ownership interest in
     EEI, 40% owned by AmerenUE and 20% owned by Resources Company.
o    Ameren Services  Company (Ameren  Services),  which provides shared support
     services to Ameren and its  subsidiaries,  including us.  Charges are based
     upon the actual  costs  incurred  by Ameren  Services,  as  required by the
     PUHCA.

     You should read the following discussion and analysis in conjunction with:
o    The  financial  statements  and related  notes  included in this  Quarterly
     Report on Form 10-Q.
o    Management's  Discussion and Analysis of Financial Condition and Results of
     Operations  that is included in our 2002 Annual Report on Form 10-K for the
     period ended December 31, 2002.
o    The audited financial statements and related notes that are included in our
     2002 Annual Report on Form 10-K for the period ended December 31, 2002.

     When we refer to  AmerenCIPS,  our, we or us, we are  referring  to Central
Illinois  Public  Service  Company.  All tabular dollar amounts are in millions,
unless otherwise indicated.

     Our results of  operations  and  financial  position  are  impacted by many
factors,  including  both  controllable  and  uncontrollable  factors.  Weather,
economic  conditions,  and the  actions  of key  customers  or  competitors  can
significantly impact the demand for our services.  Our results are also impacted
by seasonal  fluctuations  caused by winter heating and summer  cooling  demand.
With nearly all of our



                                       12

<PAGE>

revenues  directly subject to regulation by various state and federal  agencies,
decisions by  regulators  can have a material  impact on the price we charge for
our  services.  We  principally  utilize  electric  power and natural gas in our
operations.  The prices for these commodities can fluctuate significantly due to
the world economic and political environment, weather and many other factors. We
do not have a purchased  power  recovery  mechanism in Illinois for our electric
utility  business,  but we do have a gas  cost  recovery  mechanism  for our gas
utility  business.  In addition,  our electric rates in Illinois are largely set
through 2006. We employ  various risk  management  strategies in order to try to
reduce our exposure to commodity risks and other risks inherent in our business.
The reliability of our transmission and distribution  systems,  and the level of
operating and  administrative  costs and capital investment are key factors that
we seek to control in order to optimize  our results of  operations,  cash flows
and financial position.


RESULTS OF OPERATIONS

Earnings Summary

     Our net income of $2 million for the three  months ended March 31, 2003 was
comparable  to the same period of 2002.  Gas margins  improved by $3 million and
electric margins improved by $1 million in the first quarter of 2003 principally
due  to   increased   demand,   resulting   from   colder   weather   than   the
warmer-than-normal  weather conditions in the first quarter of 2002. The benefit
of the higher gas and electric  margins was offset by lower  interest  income on
our note  receivable  from  Generating  Company  (less than $1  million,  net of
taxes),  the loss of earnings  from the  transfer of our 20%  interest in EEI to
Resources  Company on April 30,  2002 (less than $1  million,  net of taxes) and
increased depreciation (less than $1 million, net of taxes).

Recent Developments

Acquisitions

     On  January  31,  2003,  Ameren  completed  its  acquisition  of all of the
outstanding  common  stock of CILCORP from The AES  Corporation.  CILCORP is the
parent company of Peoria,  Illinois-based  Central Illinois Light Company, which
operated as CILCO. With the acquisition,  CILCO became an Ameren subsidiary, but
remains a separate  utility  company,  operating as AmerenCILCO.  On February 4,
2003,  Ameren also completed its acquisition of AES Medina Valley Cogen (No. 4),
LLC (Medina  Valley),  which indirectly owns a 40 megawatt,  gas-fired  electric
generation plant. With the acquisition,  Medina Valley,  which Ameren renamed as
AmerenEnergy Medina Valley Cogen (No. 4), LLC, became a wholly-owned  subsidiary
of Resources  Company.  The results of operations  for CILCORP and  AmerenEnergy
Medina  Valley  Cogen  (No.  4),  LLC were  included  in  Ameren's  consolidated
financial  statements  effective with the January and February 2003  acquisition
dates.  Our results of operations  for the quarter ended March 31, 2003 were not
impacted by these acquisitions.

     Ameren  acquired  CILCORP  to  complement  its  existing  Illinois  gas and
electric operations.  The purchase included CILCO's rate-regulated  electric and
natural gas  businesses in Illinois  serving  approximately  200,000 and 205,000
customers, respectively, of which approximately 150,000 are combination electric
and gas  customers.  CILCO's  service  territory  is  contiguous  to our service
territory.  CILCO  also  has a non  rate-regulated  electric  and gas  marketing
business  principally  focused in the Chicago,  Illinois  region.  Finally,  the
purchase included approximately 1,200 megawatts of largely coal-fired generating
capacity, most of which is expected to become non rate-regulated in 2003.

     The total  purchase price was  approximately  $1.4 billion and included the
assumption of CILCORP and Medina  Valley debt and preferred  stock at closing of
approximately  $895 million and  consideration of approximately  $488 million in
cash,  including related  acquisition costs, net of cash acquired.  The purchase
price is subject to certain  adjustments  for working  capital and other changes
pending the finalization of CILCORP's  closing balance sheet. The cash component
of the purchase  price came from  Ameren's  issuances in September  2002 of 8.05
million  common  shares and its  issuance in early 2003 of an  additional  6.325
million  common shares which together  generated  aggregate net proceeds of $575
million.



                                       13

<PAGE>

Credit Ratings

     In April 2002, as a result of  AmerenUE's  then pending  Missouri  electric
earnings  complaint case and the CILCORP  transaction and related  assumption of
debt,  credit rating agencies placed Ameren's and its  subsidiaries'  debt under
review.  Following the completion of the acquisition of CILCORP in January 2003,
Standard & Poor's  lowered the ratings of Ameren,  AmerenUE and us and increased
the ratings of Generating  Company,  CILCORP and AmerenCILCO.  At the same time,
Standard & Poor's  changed  the  outlook  assigned  to all of  Ameren's  and its
subsidiaries'  ratings to stable.  Moody's also lowered  Ameren's and AmerenUE's
ratings  subsequent to the  acquisition and changed the outlook on these ratings
to stable.  These actions were consistent with the actions the ratings  agencies
disclosed they were considering  following Ameren's  announcement of the CILCORP
acquisition.

     As of April 30,  2003,  selected  ratings by Moody's and  Standard & Poor's
were as follows:

--------------------------------------------------------------------------------
                                                 Moody's    Standard & Poor's
--------------------------------------------------------------------------------
Ameren Corporation:
     Issuer/Corporate credit rating                A3               A-
     Unsecured debt                                A3             BBB+
     Commercial paper                             P-2              A-2

AmerenUE:
     Secured debt                                  A1               A-
     Unsecured debt                                A2             BBB+
     Commercial paper                             P-1              A-2

CILCORP:
     Unsecured debt                              Baa2             BBB+

AmerenCILCO:
     Secured debt                                  A2               A-

AmerenCIPS:
     Secured debt                                  A1               A-
     Unsecured debt                                A2             BBB+

Generating Company:
     Unsecured debt                           A3/Baa2               A-
--------------------------------------------------------------------------------

     Any  adverse  change  in our,  Ameren's  or its  other  subsidiaries'credit
ratings may reduce our access to capital and/or increase the costs of borrowings
resulting  in  a  negative  impact  on  earnings.  A  credit  rating  is  not  a
recommendation  to  buy,  sell  or  hold  securities  and  should  be  evaluated
independently of any other rating. Ratings are subject to revision or withdrawal
at any time by the assigning rating organization.

Electric Operations

     The following  table  represents the favorable  (unfavorable)  variation on
electric  margins for the three months ended March 31, 2003 from the  comparable
period in 2002:

--------------------------------------------------------------------------------
                                                                 Three Months
--------------------------------------------------------------------------------
Electric Revenues:
    Effect of weather (estimate)                                   $  5
    Wholesale sales                                                   1
    Interchange sales                                                (2)
    Growth and other (estimate)                                     (22)
--------------------------------------------------------------------------------
Total variation in electric operating revenues                     $(18)
Purchased power variation:                                         $ 19
--------------------------------------------------------------------------------
Change in electric margins                                         $  1
--------------------------------------------------------------------------------

                                       14

<PAGE>

     Electric margins  increased $1 million for the three months ended March 31,
2003  compared to the same period in 2002  principally  due to increased  demand
resulting  from colder winter  weather as weather  sensitive  residential  sales
increased 16% for the first  quarter of 2003 compared to 2002.  During the first
quarter of 2003 industrial and commercial  revenues and corresponding  purchased
power  declined  approximately  $19 million  resulting  from  certain  customers
electing to switch to our affiliate,  Marketing Company, for their energy supply
and the impact of the soft economy.

Gas Operations

     Our gas margins  increased  $3 million for the three months ended March 31,
2003  compared  to the same  period in 2002 gas  revenues  and  costs  increased
primarily due to increased  customer demand resulting from colder winter weather
in the  first  quarter  of 2003 as well as,  gas costs  increased  due to higher
natural gas prices and increased purchases.

Other Operating Expenses

Other Operations and Maintenance

     Other  operations  and  maintenance  expenses  increased $1 million for the
three months ended March 31, 2003 compared to the same period in 2002  primarily
due to higher employee benefit costs related to increasing  healthcare costs and
investment  performance of employee benefit plan assets ($2 million),  partially
offset by  decreased  professional  services  expenses  related  to  information
technology in 2002 ($1 million).

     Ameren Services provided services to us including wages,  employee benefits
and professional services that were included in other operations and maintenance
expenses.  See Note 4 - Related Party  Transactions to our Financial  Statements
under Item 1 of Part I of this report for further information.

Depreciation and Amortization

     Depreciation  and amortization  expenses  increased $1 million in the first
three  months of 2003  compared to the same period in 2002  primarily  resulting
from transmission and distribution related additions.

Income Taxes

     Income taxes were comparable for the three months ended 2003 and 2002.

Other Income and Deductions

     Other income and deductions  (excluding  income taxes) decreased $3 million
in the first three months of 2003 compared to the same period in 2002  primarily
due  to  less  intercompany   interest   received  on  the  Generating   Company
subordinated   promissory  note  as  a  result  of  a  lower  principal  balance
outstanding ($1 million), lower earnings from EEI due to the transfer of our 20%
common stock interest in EEI to Resources Company on April 30, 2002 ($1 million)
and a decrease in contributions in aid of construction ($1 million).

Interest

     Interest  expense  decreased  $1 million for the first three months of 2003
compared to the similar period in 2002,  primarily due to less interest  expense
resulting  from the  redemption of first  mortgage bonds in the third quarter of
2002.

                                       15

<PAGE>
LIQUIDITY AND CAPITAL RESOURCES

Operating

     Cash  provided by operating  activities  was $41 million in the first three
months of 2003  compared to $11 million in the first three  months of 2002.  The
increase was  primarily due to less cash used in Accounts and Wages payable than
in the first quarter of 2002.  Lower sales and power  purchases  resulting  from
certain customers electing to switch to our affiliate,  Marketing  Company,  for
their energy  supply and the timing  impact on working  capital  resulted in the
decrease.

     Our tariff-based  gross margins continue to be our principal source of cash
from operating activities. Our diversified retail customer mix of rate-regulated
residential,  commercial and  industrial  classes and a commodity mix of gas and
electric  service  provide a  reasonably  predictable  source of cash flows.  In
addition,  we plan to utilize  short-term debt to support normal  operations and
other temporary capital requirements.  In 2002, all of our Illinois residential,
commercial and industrial customers had choice in electric suppliers as provided
by the Electric  Service  Customer  Choice and Rate Relief Law of 1997.  Several
commercial  and  industrial  customers  switched to Marketing  Company for their
energy  supply  resulting  in a  decline  in our  revenues  and a  corresponding
decrease in purchased power of  approximately  $19 million for the first quarter
of 2003. We continue to incur delivery  service costs and charge related tariffs
associated with these customers.


Investing

     Our net cash used in  investing  activities  was $17  million for the three
months ended March 31, 2003 while net cash provided by investing  activities was
$6 million for the same period in 2002.  The  difference  was  primarily  due to
increased  intercompany  money pool  investments  and a decrease in construction
expenditures.  Capital  expenditures for  transmission and distribution  related
activities are expected to approximate $55 million in 2003.

Financing

     Our cash flows used in financing  activities were $25 million for the three
months  ended  March 31,  2003 as compared to $21 million for the same period in
2002. Our principal  financing  activities for the three month periods  included
the payment of dividends, as well as redemptions of long-term debt. The increase
in cash used in financing  activities  was  primarily  due to an increase in the
payment of dividends on our common stock.

     We are  authorized by the SEC under the PUHCA to have up to $250 million of
short-term unsecured debt instruments outstanding at any time.

Short-Term Debt and Liquidity

     Short-term  debt typically  consists of borrowings  under Ameren's  utility
money pool  agreement  but,  from time to time,  may also consist of  commercial
paper and bank loans  (maturities  generally  within 1 to 45 days). At March 31,
2003, Ameren and its subsidiaries had committed credit  facilities,  expiring at
various  dates  between  2003  and  2005,   totaling  $694  million,   excluding
AmerenCILCO facilities of $60 million, EEI of $45 million and AmerenUE's nuclear
fuel lease  facilities of $120 million.  This amount includes $15 million of our
committed bank lines of credit and $679 million of committed  credit  facilities
at Ameren and AmerenUE.  We access these combined  facilities  through  Ameren's
utility  money pool  arrangement.  AmerenUE and Ameren  Services may also borrow
under this  arrangement.  These  committed  credit  facilities  are also used to
support  AmerenUE's  commercial  paper  program,  all of which  was  unused  and
available at March 31, 2003.

     Subject to the  receipt of  regulatory  approval,  which is being  pursued,
AmerenCILCO will participate in Ameren's utility money pool  arrangement.  Under
this  arrangement,  AmerenCILCO  will  have  access  to up to  $694  million  of
additional committed  liquidity,  subject to reduction based on the use by other
utility

                                       16

<PAGE>

money pool  participants,  but  increased to the extent other pool  participants
have surplus cash balances,  which may be used to fund pool needs.  At March 31,
2003,  AmerenCILCO had committed  credit  facilities,  expiring at various dates
during  2003,  totaling  $60  million,  one of which  totaling  $25  million was
subsequently renewed to 2004.

     On April 1, 2003,  AmerenUE  entered into an additional  364-day  committed
credit facility totaling $75 million to be used for general corporate  purposes,
including  support of commercial paper programs.  This facility makes borrowings
available  at various  interest  rates  based on LIBOR,  agreed  rates and other
options. We and Ameren can access this facility through the utility money pool.

     Our affiliate, EEI also has two bank credit agreements totaling $45 million
that expire in 2003.  At March 31,  2003,  $32 million was unused and  available
under these committed credit facilities.

     AmerenUE  also has a lease  agreement  that  provides for the  financing of
nuclear fuel. At March 31, 2003, the maximum amount that could be financed under
the  agreement was $120  million.  At March 31, 2003,  $111 million was financed
under the lease.

     In addition to committed credit  facilities,  a further source of liquidity
for Ameren is available cash and cash equivalents. At March 31, 2003, Ameren had
$260 million of cash,  all of which was  available for borrowing by us under the
utility  money  pool.  In the  first  quarter  of 2003,  Ameren  paid a total of
approximately $488 million of cash on hand, including related acquisition costs,
net of cash acquired to acquire CILCORP and Medina Valley.

     We  rely on  access  to  short-term  and  long-term  capital  markets  as a
significant  source of funding for capital  requirements  not  satisfied  by our
operating cash flows.  The inability by us to raise capital on favorable  terms,
particularly  during  times  of  uncertainty  in  the  capital  markets,   could
negatively impact our ability to maintain and grow our businesses.  Based on our
current credit  ratings,  we believe that we will continue to have access to the
capital markets.  However,  events beyond our control may create  uncertainty in
the capital  markets such that our cost of capital would increase or our ability
to access the capital markets would be adversely affected.

Financial Agreement Provisions and Covenants

     Ameren's and our financial  agreements include customary default provisions
that  could  impact  the  continued  availability  of  credit  or  result in the
acceleration  of  repayment.  Ameren's and its  subsidiaries'  committed  credit
facilities  require the borrower to represent,  in connection with any borrowing
under the facility that no material  adverse  change has occurred  since certain
dates. None of our, Ameren's nor its other subsidiaries'  financing arrangements
contain  credit  rating  triggers,  except for three  funded  bank term loans at
AmerenCILCO totaling $105 million at March 31, 2003.

     Ameren's  and  its  subsidiaries'   committed  credit  facilities   include
provisions  related  to the  funded  status  of  Ameren's  pension  plan.  These
provisions  either require  Ameren to meet minimum  Employee  Retirement  Income
Security  Act of  1974  (ERISA)  funding  requirements  or  limit  the  unfunded
liability  status of the plan.  Under the most  restrictive of these  provisions
impacting Ameren's  facilities  totaling $400 million,  an event of default will
result if the unfunded  liability  status (as defined in the  underlying  credit
agreements)  of Ameren's  pension plan  exceeds  $300 million in the  aggregate.
Based on the most recent  valuation  report  available to Ameren at December 31,
2002,  which was based on  January  2002  asset and  liability  valuations,  the
unfunded  liability  status  (as  defined)  was $31  million.  While an  updated
valuation  report will not be  available  until the second half of 2003,  Ameren
believes  that the unfunded  liability  status of its pension plans (as defined)
could exceed $300 million  based on the  investment  performance  of the pension
plan assets and interest rate changes since January 1, 2002. As a result, Ameren
may need to  renegotiate  the  facility  provisions,  terminate  or replace  the
affected  facilities,  or fund any unfunded liability  shortfall.  Should Ameren
elect to terminate  these  facilities,  Ameren  believes it would otherwise have
sufficient liquidity to manage its short-term funding requirements.

     At March 31,  2003,  Ameren and its  subsidiaries,  including  us,  were in
compliance with their financial agreement provisions and covenants.

                                       17

<PAGE>

Off-Balance Sheet Arrangements

     At March 31, 2003, neither Ameren,  nor any of its subsidiaries,  including
us, had any  off-balance  sheet  financing  arrangements,  other than  operating
leases entered into in the ordinary course of business.  At this time, we do not
expect to engage in any significant off-balance sheet financing arrangements.

OUTLOOK

     We believe  there will be  challenges to earnings in 2003 and beyond due to
industry-wide trends and company-specific  issues. The following are expected to
put pressure on earnings in 2003 and beyond:

o    Weak economic conditions, which impact native load demand,
o    The adverse effects of rising employee  benefit costs and higher  insurance
     costs, and
o    An assumed return to more normal weather patterns relative to 2002.

     In late 2002, we and Ameren announced the following actions to mitigate the
effect of these challenges:

o    A voluntary  retirement  program  that was  accepted by  approximately  550
     Ameren  employees,   including   approximately  70  of  our  employees  and
     additional  employees  providing  support  functions  to us through  Ameren
     Services,
o    Modifications to retiree employee benefit plans to increase co-payments and
     limit Ameren's overall cost,
o    A  wage  freeze  in  2003  for  all  management  employees,  including  our
     employees, and
o    Reductions of 2003 expected capital expenditures.

     We are pursuing an annual gas rate increase of approximately $16 million in
Illinois. Ameren is also considering additional actions, including modifications
to active employee benefits, further staffing reductions and other initiatives.

     In early May 2003, our service territory  experienced several severe storms
that damaged parts of our transmission and distribution  system. As a result, we
expect to incur  increased costs in the quarter ending June 30, 2003 for repairs
required to our system.  We are  currently  unable to estimate the impact on our
future financial position, results of operations or cash flows.

     In the  ordinary  course  of  business,  we  and  Ameren  evaluate  several
strategies  to  enhance  our  financial  position,  results  of  operations  and
liquidity.  These strategies may include potential  acquisitions,  divestitures,
opportunities  to  reduce  costs  or  increase   revenues  and  other  strategic
initiatives in order to increase  Ameren's  shareholder  value. We are unable to
predict which,  if any, of these  initiatives  will be executed,  as well as the
impact these initiatives may have on our future financial  position,  results of
operations or liquidity.


REGULATORY MATTERS

     See Note 2 - Rate and Regulatory Matters to our Financial  Statements under
Item 1 of Part I of this report for more information.


ACCOUNTING MATTERS

Critical Accounting Policies

     Preparation  of  the  financial   statements  and  related  disclosures  in
compliance  with  generally   accepted   accounting   principles   requires  the
application of appropriate  technical accounting rules and guidance,  as well as
the use of estimates.  Our  application  of these  policies  involves  judgments
regarding many factors, which, in and of themselves, could materially impact the
financial  statements  and  disclosures.  A future change in the  assumptions or
judgments applied in determining the following matters, among others, could have
a material  impact on future  financial  results.  In the table  below,  we have
outlined  those  accounting   policies  that  we  believe  are  most  difficult,
subjective or complex:


                                       18

<PAGE>

<TABLE>
<CAPTION>

Accounting Policy                                  Uncertainties Affecting Application
-----------------                                  ------------------------------------
<S><C>                                            <C><C>
Regulatory Mechanisms and Cost Recovery
   We defer costs as regulatory assets in          o  Regulatory environment, external regulatory
   accordance with SFAS 71 and make investments       decisions and requirements
   that we assume we will be able to collect in    o  Anticipated future regulatory decisions and their
   future rates.                                      impact
                                                   o  Impact of deregulation and competition on
                                                      ratemaking process and ability to recover costs

   Basis for Judgment
   We determine that costs are recoverable  based on previous rulings by state
   regulatory  authorities in jurisdictions  where we operate or other factors
   that lead us to believe that cost recovery is probable.


Environmental Costs
   We accrue for all known environmental           o  Extent of contamination
   contamination where remediation can be          o  Responsible party determination
   reasonably estimated, but some of our           o  Approved methods for cleanup
   operations have existed for over 100 years      o  Present and future legislation and governmental
   and previous contamination may be unknown to       regulations and standards
   us.                                             o  Results of ongoing research and development
                                                      regarding environmental impacts
                                                   o  Indemnification obligations

   Basis for Judgment
   We determine the proper amounts to accrue for  environmental  contamination
   based on  internal  and third  party  estimates  of  clean-up  costs in the
   context of current remediation standards and available technology.


Unbilled Revenue
   At the end of each period, we estimate, based   o  Projecting customer energy usage
   on expected usage, the amount of revenue to     o  Estimating impacts of weather and other usage-
   record for services that have been provided        affecting factors for the unbilled period
   to customers, but not billed.  This period
   can be up to one month.

   Basis for Judgment
   We determine  the proper  amount of unbilled  revenue to accrue each period
   based on the  volume of energy  delivered  as valued by a model of  billing
   cycles and  historical  usage  rates and growth by  customer  class for our
   service  area,  as adjusted for the modeled  impact of seasonal and weather
   variations based on historical results.


                                       19
<PAGE>


Accounting Policy (Continued)                      Uncertainties Affecting Application (Continued)
-----------------------------                      -----------------------------------------------
Benefit Plan Accounting
   Based on actuarial calculations, we accrue      o  Future rate of return on pension and other plan
   costs of providing future employee benefits        assets
   in accordance with SFAS 87, 106, and 112.       o  Interest rates used in valuing benefit obligations
   See Note 11 - Retirement Benefits to our        o  Healthcare costs trend rates
   Financial Statements in our 2002 Annual         o  Timing of employee retirements
   Report on Form 10-K.                            o  Future plan designs

   Basis for Judgment
   We  utilize  a third  party  consultant  to  assist  us in  evaluating  and
   recording  the proper  amount for future  employee  benefits.  Our ultimate
   selection of the discount rate,  healthcare trend rate and expected rate of
   return on  pension  assets is based on our  review  of  available  current,
   historical and projected rates, as applicable.
</TABLE>


ITEM 3. Quantitative And Qualitative Disclosures About Market Risk.

     Market risk  represents the risk of changes in value of a physical asset or
a financial instrument, derivative or non-derivative,  caused by fluctuations in
market  variables  (e.g.,  interest rates,  etc.).  The following  discussion of
Ameren's,   including  our  company's,   risk  management   activities  includes
"forward-looking"  statements  that  involve  risks  and  uncertainties.  Actual
results could differ  materially from those  projected in the  "forward-looking"
statements. Ameren handles market risks in accordance with established policies,
which may include entering into various derivative  transactions.  In the normal
course of  business,  Ameren  and our  company  also face  risks that are either
non-financial or  non-quantifiable.  Such risks  principally  include  business,
legal and operational risks and are not represented in the following discussion.

     Ameren's risk management  objective is to optimize its physical  generating
assets within prudent risk  parameters.  Risk  management  policies are set by a
Risk Management  Steering  Committee,  which is comprised of senior-level Ameren
officers.

Interest Rate Risk

     We are exposed to market risk through changes in interest rates  associated
with both long-term and short-term  variable-rate  debt and fixed-rate debt, and
auction-rate   preferred   stock.  We  manage  our  interest  rate  exposure  by
controlling   the  amount  of  these   instruments  we  hold  within  our  total
capitalization  portfolio  and by  monitoring  the effects of market  changes in
interest rates.

     Utilizing  our debt  outstanding  at March  31,  2003,  if  interest  rates
increased by 1%, our annual  interest  expense and  dividend on preferred  stock
would  increase by  approximately  $0.3 million and net income would decrease by
approximately  $0.3  million.  The model does not  consider  the  effects of the
reduced level of potential overall economic activity that would exist in such an
environment.  In the event of a significant change in interest rates, management
would likely take actions to further  mitigate our exposure to this market risk.
However,  due to the uncertainty of the specific actions that would be taken and
their  possible  effects,  the  sensitivity  analysis  assumes  no change in our
financial structure.


                                       20

<PAGE>

Equity Price Risk

     We, along with other  subsidiaries of Ameren, are a participant in Ameren's
defined  benefit and  post-retirement  benefit plans and are responsible for our
proportional  share of the costs.  Ameren's costs of providing  non-contributory
defined benefit retirement and post-retirement  benefit plans are dependent upon
a number of factors, such as the rates of return on plan assets,  discount rate,
the rate of increase in health care costs and  contributions  made to the plans.
The market  value of Ameren's  plan assets has been  affected by declines in the
equity market since 2000 for the pension and post-retirement plans. As a result,
at December 31, 2002 Ameren and its  subsidiaries,  including us,  recognized an
additional  minimum pension liability as prescribed by SFAS No. 87,  "Employers'
Accounting for  Pensions." The liability  resulted in a reduction to equity as a
result of a charge to Ameren's  Accumulated Other Comprehensive  Income (OCI) of
$102 million,  net of taxes.  Our portion of this charge to OCI was $13 million,
net of  taxes.  The  amount of the  liability  was the  result of asset  returns
experienced through 2002, interest rates and Ameren's contributions to the plans
during 2002.  Neither Ameren's nor our portion of the minimum pension  liability
changed at March 31, 2003. In future years,  the liability  recorded,  the costs
reflected  in net  income,  or OCI,  or cash  contributions  to the plans  could
increase  materially  without a recovery in equity markets in excess of Ameren's
assumed return on plan assets. If the fair value of the plan assets were to grow
and exceed the accumulated  benefit obligations in the future, then the recorded
liability  would be  reduced  and a  corresponding  amount  of  equity  would be
restored in the Balance Sheet.

ITEM 4.  Controls and Procedures.

     (a) Evaluation of Disclosure Controls and Procedures

     Within  90 days  prior  to the  date  of this  report,  we  carried  out an
evaluation,  under the  supervision  and with  participation  of our management,
including  our chief  executive  officer  and chief  financial  officer,  of the
effectiveness  of the  design  and  operation  of our  disclosure  controls  and
procedures pursuant to Rule 13a-14 under the Securities Exchange Act of 1934, as
amended.  Based upon that  evaluation,  the chief  executive  officer  and chief
financial  officer  concluded  that our  disclosure  controls and procedures are
effective  in  timely  alerting  them  to  material   information   relating  to
AmerenCIPS, which is required to be included in our periodic SEC filings.

     (b) Change in Internal Controls

     There have been no significant changes in our internal controls or in other
factors which could  significantly  affect internal  controls  subsequent to the
date we carried out our evaluation.

FORWARD-LOOKING STATEMENTS

     Statements made in this report which are not based on historical  facts are
"forward-looking"  and, accordingly,  involve risks and uncertainties that could
cause actual results to differ  materially from those  discussed.  Although such
"forward-looking"  statements  have  been  made in good  faith  and are based on
reasonable assumptions,  there is no assurance that the expected results will be
achieved.  These statements include (without limitation) statements as to future
expectations,  beliefs, plans, strategies,  objectives,  events,  conditions and
financial  performance.  In connection with the "safe harbor"  provisions of the
Private  Securities  Litigation  Reform  Act  of  1995,  we are  providing  this
cautionary  statement  to identify  important  factors  that could cause  actual
results to differ materially from those anticipated.  The following factors,  in
addition  to  those  discussed  elsewhere  in  this  report  and  in  subsequent
securities  filings and others,  could cause results to differ  materially  from
management expectations as suggested by such "forward-looking" statements:

o    the effects of regulatory actions, including changes in regulatory policy;
o    changes in laws and other  governmental  actions,  including  monetary  and
     fiscal policies;
o    the impact on us of current  regulations  related  to the  opportunity  for
     customers to choose alternative energy suppliers in Illinois;
o    the  effects of  increased  competition  in the future due to,  among other
     things,  deregulation  of certain aspects of our business at both the state
     and federal levels;


                                       21

<PAGE>

o    the   effects   of   participation   in   a   Federal   Energy   Regulatory
     Commission-approved    Regional   Transmission   Organization,    including
     activities associated with the Midwest Independent System Operator;
o    availability and future market prices for purchased power,  electricity and
     natural gas for distribution, including the use of financial and derivative
     instruments  and  volatility of changes in market prices and our ability to
     recover increased costs;
o    average rates for electricity in the Midwest;
o    business and economic conditions;
o    the impact of the adoption of new accounting  standards on the  application
     of appropriate technical accounting rules and guidance;
o    interest rates and the availability of capital;
o    actions of rating agencies and the effects of such actions;
o    weather conditions;
o    the  effects  of  strategic   initiatives,   including   acquisitions   and
     divestitures;
o    the  impact of  current  environmental  regulations  on  utilities  and the
     expectation that more stringent  requirements will be introduced over time,
     which could potentially have a negative financial effect;
o    future wages and employee  benefit costs,  including  changes in returns of
     benefit plan assets;
o    disruptions of the capital  markets or other events making Ameren's and our
     access to necessary capital more difficult or costly;
o    cost and  availability  of  transmission  capacity  required to satisfy our
     energy sales; and
o    legal and administrative proceedings.

     Given these  uncertainties,  undue  reliance  should not be placed on these
forward-looking  statements.  Except  to the  extent  required  by  the  federal
securities  laws, we undertake no  obligation  to publicly  update or revise any
forward-looking  statements,  whether  as a result  of new  information,  future
events or otherwise.


                                       22

<PAGE>

                           PART II. OTHER INFORMATION

ITEM 1.  Legal Proceedings.

     Reference  is made  to  Note 12  under  Item 8  "Financial  Statements  and
Supplementary Data" in Part II of our 2002 Annual Report on Form 10-K and Note 7
under Item 8 "Financial  Statements  and  Supplementary  Data" in Part II of the
2002 Annual  Report on Form 10-K of our  affiliates,  CILCORP  Inc.  and Central
Illinois Light Company,  operating as AmerenCILCO,  for a discussion of a number
of lawsuits  that name our  affiliates,  Union  Electric  Company,  operating as
AmerenUE, AmerenCILCO, our parent, Ameren Corporation, and us (which we refer to
as the Ameren companies),  along with numerous other parties, as defendants that
have been filed by plaintiffs  claiming  varying degrees of injury from asbestos
exposure.  Since  the  filing  of the  2002  Annual  Reports  on Form  10-K,  25
additional  lawsuits have been filed against us and AmerenUE,  but no additional
lawsuits have been filed against AmerenCILCO.  These lawsuits, like the previous
cases,  were mostly  filed in the  Circuit  Court of Madison  County,  Illinois,
involve a large  number of total  defendants  and seek  unspecified  damages  in
excess of $50,000,  which, if proved,  typically would be shared among the named
defendants.  Also since the filing of the 2002 Annual  Reports on Form 10-K, the
Ameren  companies have been  voluntarily  dismissed in 58 cases and have settled
six cases.

     To date, a total of 152  asbestos-related  lawsuits have been filed against
the Ameren companies,  of which 72 are pending, 16 have been settled and 64 have
been dismissed.  We believe that the final disposition of these proceedings will
not have a  material  adverse  effect  on our  financial  position,  results  of
operations or liquidity.

     Note 2 - Rate and Regulatory Matters to our Financial Statements under Item
1 of Part I of this report contains additional  information on an administrative
proceeding which is incorporated by reference under this item.


ITEM 6.  Exhibits and Reports on Form 8-K.

      (a)(i)   Exhibits filed herewith.

               99.1 - Certificate of Chief Executive Officer required by Section
                      906 of the Sarbanes-Oxley Act of 2002.

               99.2 - Certificate of Chief Financial Officer required by Section
                      906 of the Sarbanes-Oxley Act of 2002.

      (a)(ii)  Exhibits incorporated by reference.

               10.1 - *2003  Ameren  Executive  Incentive  Plan  (Ameren
                       Corporation  quarterly  report  on  Form  10-Q  for the
                       quarter ended March 31, 2003, Exhibit 10.1)

      (b)      Reports  on Form 8-K.  AmerenCIPS  filed no reports on Form 8-K
               during the quarterly period ended March 31, 2003.

      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 Union Electric Company on Forms 8-K, 10-Q and 10-K are
               on file with the SEC under File Number 1-2967.

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

---------------------
               * Management compensatory plan or arrangement.


                                       23
<PAGE>

               Reports of CILCORP  Inc. on Forms 8-K,  10-Q and 10-K are on file
               with the SEC under File Number 2-95569.

               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.




                                    SIGNATURE

     Pursuant to the  requirements  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.

                                             CENTRAL ILLINOIS PUBLIC
                                              SERVICE COMPANY
                                              (Registrant)

                                             By  /s/ Martin J. Lyons
                                               ----------------------------
                                                     Martin J. Lyons
                                               Vice President and Controller
                                               (Principal Accounting Officer)
Date:  May 14, 2003




                                 CERTIFICATIONS

     I, Gary L. Rainwater, certify that:

     1. I have reviewed this quarterly  report on Form 10-Q of Central  Illinois
Public Service Company;

     2. Based on my knowledge, this quarterly 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 quarterly
report;

     3. Based on my knowledge,  the financial  statements,  and other  financial
information  included in this quarterly  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 quarterly 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 we 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
               quarterly 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 quarterly report (the "Evaluation Date"); and


                                       24


<PAGE>


                           CERTIFICATIONS (CONTINUED)

        c)     presented  in this  quarterly  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
function):

        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
quarterly  report  whether or not 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:  May 14, 2003                            /s/ Gary L. Rainwater
                                           -------------------------------------
                                                   Gary L. Rainwater
                                           President and Chief Executive Officer
                                                (Principal Executive Officer)


     I, Warner L. Baxter, certify that:

     1. I have reviewed this quarterly  report on Form 10-Q of Central  Illinois
Public Service Company;

     2. Based on my knowledge, this quarterly 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 quarterly
report;

     3. Based on my knowledge,  the financial  statements,  and other  financial
information  included in this quarterly  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 quarterly 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 we 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
               quarterly 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 quarterly report (the "Evaluation Date"); and


                                       25

<PAGE>


                           CERTIFICATIONS (CONTINUED)

        c)     presented  in this  quarterly  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
function):

        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
quarterly  report  whether or not 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:  May 14, 2003                          /s/ Warner L. Baxter
                                           -------------------------------
                                                 Warner L. Baxter
                                           Senior Vice President, Finance
                                             (Principal Financial Officer)

                                       26