<PAGE>

                                  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 Quarterly Period Ended March 31, 1999

[ ]  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   .


Shares  outstanding of each of registrant's  classes of common stock as of April
  30, 1999:  Common  Stock,  no par value,  held by Ameren  Corporation  (parent
  company of Registrant) - 25,452,373


<PAGE>


                     Central Illinois Public Service Company

                                      Index

                                                                       Page No.

Part I       Financial Information (Unaudited)

             Quantitative and Qualitative Disclosure
             About Market Risk                                            6

             Management's Discussion and Analysis                         2

             Balance Sheet
             - March 31, 1999 and December 31, 1998                       8

             Statement of Income
             - Three months and 12 months ended
                March 31, 1999 and 1998                                   9

             Statement of Cash Flows
             - Three months ended March 31, 1999 and 1998                10

             Notes to Financial Statements                               11


Part II      Other Information                                           13


<PAGE>


                    PART I. FINANCIAL INFORMATION (UNAUDITED)

MANAGEMENT'S  DISCUSSION  AND  ANALYSIS OF  FINANCIAL  CONDITION  AND RESULTS OF
OPERATIONS

OVERVIEW

Central  Illinois  Public Service  Company  (AmerenCIPS or the  Registrant) is a
subsidiary of Ameren  Corporation  (Ameren),  a holding company registered under
the Public Utility Holding Company Act of 1935 (PUHCA).  In December 1997, Union
Electric Company  (AmerenUE) and CIPSCO  Incorporated  (CIPSCO) combined to form
Ameren,  with  AmerenUE and CIPSCO's  subsidiaries,  the  Registrant  and CIPSCO
Investment  Company (CIC),  becoming  wholly-owned  subsidiaries  of Ameren (the
Merger).

The following  discussion and analysis  should be read in  conjunction  with the
Notes  to  Financial  Statements  beginning  on page  11,  and the  Management's
Discussion and Analysis of Financial Condition and Results of Operations (MD&A),
the Audited Financial Statements and the Notes to Financial Statements appearing
in the Registrant's 1998 Form 10-K.

RESULTS OF OPERATIONS

Earnings
First  quarter  1999  earnings of $13 million  increased  $2 million from 1998's
first quarter earnings. Earnings for the 12 months ended March 31, 1999 were $79
million,  a $46 million increase from the preceding  12-month period.  Excluding
the extraordinary charge recorded in the fourth quarter of 1997 to write off the
generation-related  regulatory assets and liabilities of the Registrant's retail
electric  business,  earnings for the 12-month  period ended March 31, 1998 were
$57 million.

Earnings  fluctuated  due to many  conditions,  primarily:  weather  variations,
electric rate reductions,  competitive market forces, sales growth,  fluctuating
operating costs,  merger-related expenses,  changes in interest expense, changes
in income and property taxes, a charge for a targeted  employee  separation plan
and an extraordinary charge, as noted above.

The  significant  items  affecting  revenues,  costs  and  earnings  during  the
three-month  and  12-month  periods  ended March 31, 1999 and 1998 are  detailed
below.

Electric Operations

Electric Operating Revenues          Variations for periods ended March 31, 1999
                                          from comparable prior-year periods
--------------------------------------------------------------------------------
(Millions of Dollars)                   Three Months         Twelve Months
--------------------------------------------------------------------------------
Rate variations                            $ (3)                 $ (8)
Effect of abnormal weather                    -                    18
Growth and other                              1                    10
Interchange sales                             8                    18
--------------------------------------------------------------------------------
                                           $  6                  $ 38
--------------------------------------------------------------------------------


The $6 million  increase  in first  quarter  electric  revenues  compared to the
year-ago  quarter was  primarily  driven by increased  interchange  sales due to
strong marketing efforts and greater  interchange  opportunities.  The 2 percent
increase in residential  sales was offset by a 2 percent  decrease in commercial
sales for the three months  ended March 31, 1999,  versus the prior year period.
Industrial  sales decreased 1 percent for the three months ended March 31, 1999,
versus the prior year  period.  Interchange  sales  increased 66 percent for the
first  quarter of 1999  compared to the  year-ago  quarter.  This  increase  was
partially  offset by a  residential  rate  decrease  (see Note 5 under  Notes to
Financial Statements for further information).

Electric revenues for the 12 months ended March 31, 1999,  increased $38 million
compared to the prior  12-month  period.  The increase in revenues was primarily
driven by warm weather,  a strong regional  economy,  and increased  interchange
sales due to increased interchange opportunities.  Weather-sensitive residential
and  commercial  sales

                                      -2-

<PAGE>
  
increased  7  percent  and  4  percent,   respectively,   while  industrial  and
interchange sales grew 3 percent and 15 percent, respectively, for the 12 months
ended  March 31,  1999,  versus  the prior year  period.  These  increases  were
partially  offset by a  residential  rate decrease (see Note 5 under to Notes to
Financial Statements for further information).


Fuel and Purchased Power
                                     Variations for periods ended March 31, 1999
                                          from comparable prior-year periods
--------------------------------------------------------------------------------
(Millions of Dollars)                    Three Months            Twelve Months
--------------------------------------------------------------------------------
Fuel:
    Variation in generation                 $ 12                     $  6
    Price                                     (5)                      (8)
    Generation efficiencies and other         (4)                     (13)
Purchased power variation                      2                       14
--------------------------------------------------------------------------------
                                            $  5                     $ (1)
--------------------------------------------------------------------------------


Fuel and  purchased  power  costs  for the  first  quarter  of 1999  versus  the
comparable  prior-year  quarter  increased $5 million primarily due to increased
sales volume, partially offset by lower fuel prices and generation efficiencies.
The relatively flat fuel and purchased power costs for the 12 months ended March
31, 1999 versus the  prior-year  period were the result of increased  generation
and purchased power,  driven by higher  kilowatthour sales, offset by lower fuel
prices and generation efficiencies.

Gas Operations
Gas revenues for the quarter ended March 31, 1999, increased $2 million compared
to the year-ago quarter  primarily due to an annual $9 million Illinois gas rate
increase  effective  February 1999. This rate increase was partially offset by a
decrease  in  industrial  sales and a  decrease  in  off-system  sales of gas to
others. Gas revenues for the 12-month period ended March 31, 1999, decreased $13
million  compared  to the same  year-ago  period  primarily  due to a decline in
sales.

Gas costs for the  quarter  ended  March 31, 1999  remained  relatively  flat as
decreases in sales were offset by increases in gas prices.  Gas costs for the 12
months  ended March 31, 1999  decreased  $19  million  compared to the  year-ago
period primarily due to lower sales.

Other Operating Expenses
Other operating expense variations  reflected  recurring factors such as growth,
inflation, labor and benefit increases.

Other operations  expenses  remained flat for the first quarter of 1999 compared
to the first  quarter of 1998,  while  increasing  $17 million for the  12-month
period ended March 31, 1999 compared to the same year-ago period.  This increase
was primarily due to the charge for the targeted  separation  plan and increases
in information system-related costs.

Maintenance  expenses for the quarter ended March 31, 1999, increased $4 million
from the  comparable  year-ago  period due to increased  scheduled  fossil power
plant maintenance.

Other Taxes
Other taxes decreased  primarily due to a decrease in gross receipt taxes.  This
decrease  results  from the  restructuring  of the Illinois  public  utility tax
whereby gross receipt taxes are no longer recorded as electric revenue and gross
receipt tax expense.

Taxes
Income taxes  charged to  operating  expenses for the three months and 12 months
ended March 31, 1999,  increased $2 million and $18 million,  respectively,  due
primarily to higher pretax income.

Balance Sheet
Changes in accounts and wages payable,  taxes accrued,  other accruals and other
current assets result from the timing of various payments to taxing  authorities
and suppliers.

                                      -3-

<PAGE>

LIQUIDITY AND CAPITAL RESOURCES

Cash provided by operating  activities totaled $50 million for the quarter ended
March 31, 1999, compared to $31 million during the same 1998 period.

Cash flows used in investing activities were $22 million and $15 million for the
three  months  ended  March  31,  1999  and  1998,  respectively.   Construction
expenditures  for the  quarter  ended  March 31,  1999 for  constructing  new or
improving  existing  facilities were $22 million.  Capital  requirements for the
remainder of 1999 are expected to be principally for construction expenditures.

Cash flows used in  financing  activities  were $38 million for the three months
ended March 31, 1999,  compared to $34 million during the same 1998 period.  The
Registrant's  principal  financing  activities  for  the  quarter  included  the
redemption of $20 million of debt and the payment of dividends.

The Registrant  plans to continue  utilizing  short-term  debt to support normal
operations and other temporary requirements. The Registrant is authorized by the
Securities  and  Exchange  Commission  under PUHCA to have up to $250 million of
short-term  unsecured debt instruments  outstanding at any one time.  Short-term
borrowings  consist of bank loans  (maturities  generally on an overnight basis)
and commercial paper  (maturities  generally within 10 to 45 days). At March 31,
1999, the Registrant had committed bank lines of credit  aggregating $80 million
(of which $80 million were unused and $48 million  were  available at such date)
which make  available  interim  financing at various rates of interest  based on
LIBOR,  the bank  certificate  of deposit  rate or other  options.  The lines of
credit are renewable annually at various dates throughout the year. At March 31,
1999, the Registrant had $32 million of short-term borrowings.

Also,  Ameren has a bank credit  agreement due 2003, which permits the borrowing
of up to $200 million on a long-term  basis.  This credit agreement is available
to Ameren and its subsidiaries,  including the Registrant. As of March 31, 1999,
$180 million was available for the Registrant's use.

RATE MATTERS

In March 1999,  AmerenCIPS  filed a delivery  service  tariff with the  Illinois
Commerce  Commission  (ICC) to  comply  with the  requirements  of the  Electric
Service  Customer  Choice and Rate Relief Law of 1997. This tariff would be used
by  electric  customers  who choose to purchase  their  power from an  alternate
supplier. The ICC has until September 1, 1999 to render a decision.

See Note 5 under Notes to Financial  Statements  for further  discussion of Rate
Matters.

ELECTRIC INDUSTRY RESTRUCTURING

In December 1997, the Governor of Illinois signed the Electric  Service Customer
Choice and Rate  Relief Law of 1997 (the Law)  providing  for  electric  utility
restructuring  in Illinois.  This  legislation  introduces  competition into the
supply of electric energy in Illinois.

One of the major  provisions of the Law includes the phasing-in  through 2002 of
retail direct access,  which allows customers to choose their electric supplier.
The  phase-in  of retail  direct  access  begins on October 1, 1999,  with large
commercial and industrial  customers  principally  comprising the initial group.
The  customers  in  this  group  represent   approximately  24  percent  of  the
Registrant's total sales.  Retail direct access will be offered to the remaining
commercial  and  industrial  customers  December  31,  2000,  and access will be
offered to residential customers May 1, 2002.

YEAR 2000 ISSUE

The Year  2000  Issue  relates  to how  dates are  stored  and used in  computer
systems,  applications, and embedded systems. As the century date change occurs,
certain date-sensitive systems need to be able to recognize the year as 2000 and
not as 1900. This inability to recognize and properly treat the year as 2000 may
cause these systems to process  critical  financial and operational  information
incorrectly.   The  Registrant's  primary  concern  is  the  potential  for  any
interruption in providing electric and gas service to customers,  as well as the
potential inability to process

                                      -4-

<PAGE>

critical  financial and  operational  information  on a timely basis,  including
billing its customers, if appropriate steps are not taken to address this issue.
Management  has  developed a Year 2000 plan (Plan)  covering  Ameren,  including
AmerenCIPS, and Ameren's Board of Directors has been briefed about the Year 2000
Issue and how it may affect the Registrant.

Ameren's Plan to resolve the Year 2000 Issue involves three phases:  assessment,
planning,  and implementation/  testing.  Implementation of the Plan is directly
supervised  by each  area's  responsible  Vice  President.  A Year 2000  Project
Director  coordinates the  implementation of the Plan among functional teams who
are  addressing  issues  specific  to a  particular  area,  such as nuclear  and
non-nuclear generation facilities,  energy management systems, gas distribution,
etc. Ameren has also engaged certain outside consultants,  technicians and other
external resources to aid in formulating and implementing the Plan.

Ameren  has  completed  its   assessment   phase,   which   included   analyzing
date-sensitive  electronic hardware,  software applications and embedded systems
and has developed a compliance plan to address issues that were identified. Many
of the major  corporate  computer  systems  at  Ameren  are  relatively  new and
therefore are either Year 2000  compliant or only require  minor  modifications.
Also,   several  of  the  operating   hardware  and  embedded   systems   (i.e.,
microprocessor  chips) use analog  rather than digital  technology  and thus are
unaffected  by the  two-digit  date issue.  In  addition,  Ameren has  contacted
hundreds of vendors and suppliers to verify compliance.

Ameren has also completed its planning  phase.  Items that have been  identified
for remediation have been prioritized into groups based on their significance to
Ameren's    operations.    The    implementation/testing     phase    for    all
components/applications  is  approximately  70 percent  complete as of March 31,
1999.   Ameren   expects   to   complete    remediation   of   its   significant
components/applications by the end of the third quarter 1999.

With  respect  to  third  parties,   for  areas  that  interface  directly  with
significant  vendors,  Ameren has inventoried vendors and major suppliers and is
currently  assessing  their Year 2000 readiness  through  surveys,  websites and
personal contact. Ameren plans to follow up with major suppliers and vendors and
verify Year 2000  compliance,  where  appropriate.  Ameren has also  queried its
health insurance  providers.  To date,  Ameren is not aware of any problems that
would  materially  impact its  financial  condition,  results of  operations  or
liquidity.  However, neither Ameren nor the Registrant has the means of ensuring
that these parties will be Year 2000  compliant.  The inability of those parties
to complete their Year 2000 resolution  process could  materially  impact Ameren
and the Registrant.

Ameren is also  addressing  the impact of electric  power grid problems that may
occur outside of its own electric system.  Ameren has started Year 2000 electric
power grid impact planning through the system's various electric interconnection
affiliations and is working with the Mid-American  Interchange Network (MAIN) to
begin planning Year 2000 operational  preparedness and restoration scenarios. As
of April 1, 1999 (the latest information available),  MAIN was finished with its
assessment and planning phases and 74 percent complete with its  implementation/
testing phase. In addition,  Ameren provides monthly status reports to the North
American  Electric  Reliability  Council (NERC) to assist them in assessing Year
2000  readiness of the regional  electric  grid. As of April 1, 1999 (the latest
information available),  NERC was 99 percent complete with its assessment phase,
95 percent  complete  with its planning  phase and 75 percent  complete with its
implementation/testing  phase. The Registrant  participated in a Year 2000 drill
conducted by NERC in April 1999.  The drill focused on the testing of the backup
systems of voice and data  communications  needed to operate the electric  power
grids in the event of a partial  communication loss. The results of the drill at
Ameren were  successful.  Additional  drills are  planned.  Through the Electric
Power Research Institute (EPRI), an industry-wide effort has been established to
deal with Year 2000 problems affecting digital systems and equipment used by the
nation's electric power companies.  Under this effort,  participating  utilities
are working together to assess specific vendors' system problems and test plans.
The assessment will be shared by the industry as a whole to facilitate Year 2000
problem solving.

In addressing  the Year 2000 Issue,  Ameren will incur  internal  labor costs as
well as  external  consulting  and  other  expenses  related  to  infrastructure
enhancements necessary to prepare for the new century. Ameren estimates that its
external costs  (consulting fees and related costs) for addressing the Year 2000
Issue will range from $10 million to $15 million.  As of March 31, 1999,  Ameren
has expended  approximately  $5 million.  Ameren's  plans to complete  Year 2000
modifications  are based on  management's  best  estimates,  which  are  derived
utilizing  numerous   assumptions  of  future  events  including  the  continued
availability of certain resources,  and other factors.  However, there can be no
guarantee that these  estimates will be achieved and actual results could differ
materially  from those plans.  Specific  factors that might cause such  material
differences  include,  but are not  limited  to,  the  availability  and cost of
personnel  trained in this area,  the ability to locate and correct all relevant
computer codes, and similar uncertainties.

                                      -5-

<PAGE>

Ameren  believes  that,  with  appropriate  modifications  to existing  computer
systems/components,  updates by vendors and trading partners,  and conversion to
new  software and  hardware in the  ordinary  course of business,  the Year 2000
Issue  will  not  pose  significant  operational  problems  for the  Registrant.
However,  if such conversions are not completed in a proper and timely manner by
all  affected  parties,  the Year 2000 Issue could  result in  material  adverse
operational and financial  consequences  to the Registrant,  and there can be no
assurance  that  Ameren's  efforts,  or those of vendors and  trading  partners,
interconnection  affiliates, NERC or EPRI to address the Year 2000 Issue will be
successful.  Ameren is in the process of developing contingency plans to address
potential risks, including risks of vendor/trading  partners  noncompliance,  as
well as noncompliance of any of the Registrant's material operating systems. The
first operational contingency plan addressing power grid issues was completed in
March, 1999. Based on the findings of the Year 2000 drill,  minor  modifications
to the plan are being developed,  with an expected completion date by the end of
the second  quarter 1999.  Contingency  plans related to the business  areas are
also  expected to be completed by the end of the second  quarter  1999.  At this
time,  the Registrant is unable to predict the ultimate  impact,  if any, of the
Year 2000 Issue on the Registrant's  financial condition,  results of operations
or liquidity; however, the impact could be material.


QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

Market risk  represents the risk of changes in value of a financial  instrument,
derivative  or  non-derivative,  caused by  fluctuations  in interest  rates and
equity prices.  The following  discussion of the  Registrant'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.  The  Registrant  handles  market  risks  in
accordance with  established  policies,  which may include entering into various
derivative  transactions.  In the normal course of business, the Registrant also
faces  risks  that are  either  non-financial  or  non-quantifiable.  Such risks
principally  include  credit risk and legal risk and are not  represented in the
following analysis.

Interest Rate Risk
The  Registrant  is exposed to market risk  through  changes in  interest  rates
through its  issuance  of both  long-term  and  short-term  variable-rate  debt,
fixed-rate  debt,  commercial  paper and auction  market  preferred  stock.  The
Registrant manages its interest rate exposure by controlling the amount of these
instruments it holds within its total capitalization portfolio and by monitoring
the effects of market changes in interest rates.

If  interest  rates  increase  1  percent  in  2000 as  compared  to  1999,  the
Registrant's  interest  expense would  increase and net income would decrease by
approximately $1 million.  This amount has been determined using the assumptions
that the  Regustrant's  outstanding  variable  rate debt,  commercial  paper and
auction market preferred stock as of March 31, 1999, continued to be outstanding
throughout  2000,  and that the  average  interest  rates for these  instruments
increased 1 percent  over 1999.  The model does not  consider the effects of the
reduced  level  of  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 its 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 the
Registrant's financial structure.

Commodity Price Risk
The  Registrant  is exposed to changes in market prices for natural gas and fuel
and  purchased  power.  With regard to its natural  gas  utility  business,  the
Registrant's  exposure to changing  market prices is in large part  mitigated by
the fact that the  Registrant  has a Purchased  Gas  Adjustment  Clause (PGA) in
place.  The PGA allows the  Registrant to pass on to its customers its prudently
incurred costs of natural gas.

Since  the  Registrant  does not  have a  provision  similar  to the PGA for its
electric operations, the Registrant has entered into several long-term contracts
with various  suppliers to purchase  coal to manage its exposure to fuel prices.
With regard to the Registrant's  exposure to commodity risk for purchased power,
Ameren  has  established  a  subsidiary,   AmerenEnergy,   Inc.,  whose  primary
responsibility  includes  managing  market  risks  associated  with the changing
market prices for purchased power for the Registrant.

AmerenEnergy  utilizes  several  techniques  to  mitigate  its  market  risk for
purchased  power,  including  utilizing  derivative  financial  instruments.   A
derivative  is a contract  whose value is dependent on or derived from the value
of some underlying asset. The derivative financial instruments that AmerenEnergy
is allowed to utilize (which include

                                      -6-

<PAGE>

forward  contracts  and futures  contracts)  are  dictated by a risk  management
policy, which has been reviewed with the Auditing Committee of Ameren's Board of
Directors. Compliance with the risk management policy is the responsibility of a
risk  management  steering  committee,  consisting  of  Ameren  officers  and an
independent risk management officer at AmerenEnergy.

As of March 31, 1999, the fair value of derivative financial instruments exposed
to commodity  price risk was immaterial.  The Registrant  expects an increase in
the derivative financial instruments used to manage risk in 1999 due to expected
growth at AmerenEnergy.

SAFE HARBOR STATEMENT

Statements made in this Form 10-Q 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,
financial  performance  and the Year 2000 Issue.  In  connection  with the "Safe
Harbor" provisions of the Private Securities  Litigation Reform Act of 1995, the
Registrant is providing this cautionary  statement to identify important factors
that could cause actual  results to differ  materially  from those  anticipated.
Factors  include,  but are not limited to, the  effects of  regulatory  actions;
changes  in laws and other  governmental  actions;  competition;  future  market
prices for fuel and purchased power, electricity, and natural gas, including the
use of financial  instruments;  average  rates for  electricity  in the Midwest;
business and economic  conditions;  interest  rates;  weather  conditions;  fuel
prices and  availability;  generation  plant  performance;  monetary  and fiscal
policies; future wages and employee benefits costs; and legal and administrative
proceedings.

                                      -7-

<PAGE>

                     CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
                                  BALANCE SHEET
                                    UNAUDITED
                      (Thousands of Dollars, Except Shares)

<TABLE>
<CAPTION>


                                                                March 31,  December 31,
ASSETS                                                             1999       1998
------                                                        ------------  -----------
<S>                                                           <C>          <C>
Property and plant, at original cost:
   Electric                                                     $2,385,393   $2,381,682
   Gas                                                             261,569      259,656
                                                                ----------   ----------
                                                                 2,646,962    2,641,338
   Less accumulated depreciation and amortization                1,210,593    1,192,108
                                                                ----------   ----------
                                                                 1,436,369    1,449,230
Construction work in progress                                       29,988       16,220
                                                                ----------   ----------
         Total property and plant, net                           1,466,357    1,465,450

Other assets                                                        30,976       31,904

Current assets:
Cash and cash equivalents                                             --         10,180
   Accounts receivable - trade (less allowance for doubtful
         accounts of $2,361 and $1,714, respectively)               60,374       44,494
   Unbilled revenue                                                 43,767       53,120
   Other accounts and notes receivable                              15,237       16,486
   Materials and supplies, at average cost -
      Fossil fuel                                                   42,579       50,791
      Other                                                         35,602       36,047
   Other                                                             7,282        8,214
                                                                ----------   ----------
         Total current assets                                      204,841      219,332
Regulatory assets:
   Deferred income taxes                                            23,978       24,797
   Other                                                            22,314       22,914
                                                                ----------   ----------
         Total regulatory assets                                    46,292       47,711
                                                                ----------   ----------
Total Assets                                                    $1,748,466   $1,764,397
                                                                ==========   ==========

CAPITAL AND LIABILITIES
Capitalization:
   Common stock, no par value, authorized 45,000,000 shares -
     outstanding 25,452,373 shares                              $  120,033   $  120,033
   Retained earnings                                               451,798      455,337
                                                                ----------   ----------
         Total common stockholder's equity                         571,831      575,370
   Preferred stock not subject to mandatory redemption              80,000       80,000
   Long-term debt                                                  523,502      528,446
                                                                ----------   ----------
        Total capitalization                                     1,175,333    1,183,816
  Current liabilities:
   Current maturity of long-term debt                               60,000       60,000
   Short-term debt                                                  31,700       46,700
   Accounts and wages payable                                       56,919       61,609
   Accumulated deferred income taxes                                21,695       21,386
   Taxes accrued                                                    22,842       13,201
   Other                                                            37,571       34,454
                                                                ----------   ----------
         Total current liabilities                                 230,727      237,350
                                                                ----------   ----------
Accumulated deferred income taxes                                  229,420      234,119
Accumulated deferred investment tax credits                         34,036       34,657
Regulatory liability                                                38,217       39,621
Other deferred credits and liabilities                              40,733       34,834
                                                                ----------   ----------
Total Capital and Liabilities                                   $1,748,466   $1,764,397
                                                                ==========   ==========

</TABLE>

                                      -8-

<PAGE>

                    CENTRAL ILLINOIS PUBLIC SERVICE COMPANY 
                               STATEMENT OF INCOME
                                    UNAUDITED
                             (Thousands of Dollars)

<TABLE>
<CAPTION>

                                                             Three Months Ended        Twelve Months Ended
                                                                  March 31,                 March 31,        
                                                          ------------------------   ----------------------
                                                              1999         1998         1999         1998
                                                              ----         ----         ----         ----
<S>                                                      <C>          <C>          <C>          <C>
 OPERATING REVENUES:
   Electric                                                $ 155,240    $ 149,271    $ 727,887    $ 690,235
   Gas                                                        52,532       50,244      127,794      140,663
                                                           ---------    ---------    ---------    ---------
      Total operating revenues                               207,772      199,515      855,681      830,898

OPERATING EXPENSES:
   Operations
      Fuel and purchased power                                55,690       51,082      234,693      235,725
      Gas                                                     33,250       32,225       70,375       89,121
      Other                                                   40,398       41,294      178,581      161,944
                                                           ---------    ---------    ---------    ---------
                                                             129,338      124,601      483,649      486,790
   Maintenance                                                17,407       13,835       75,114       74,617
   Depreciation and amortization                              20,740       18,822       76,241       80,335
   Income taxes                                                5,979        4,348       47,400       29,446
   Other taxes                                                 9,599       16,177       50,256       58,011
                                                           ---------    ---------    ---------    ---------
      Total operating expenses                               183,063      177,783      732,660      729,199

OPERATING INCOME                                              24,709       21,732      123,021      101,699

OTHER INCOME AND DEDUCTIONS:
   Allowance for equity funds used during
      construction                                                (6)          46          (36)         612
   Miscellaneous, net                                            356          354         (953)      (3,221)
                                                           ---------    ---------    ---------    ---------
      Total other income and deductions                          350          400         (989)      (2,609)

INCOME BEFORE INTEREST CHARGES                                25,059       22,132      122,032       99,090

INTEREST CHARGES:
   Interest                                                   10,815       10,432       40,422       38,794
   Allowance for borrowed funds used during construction         (71)        (418)        (734)        (929)
                                                           ---------    ---------    ---------    ---------
      Net interest charges                                    10,744       10,014       39,688       37,865

INCOME BEFORE EXTRAORDINARY CHARGE                            14,315       12,118       82,344       61,225
                                                           ---------    ---------    ---------    ---------

EXTRAORDINARY CHARGE (NET OF
INCOME TAXES)                                                   --           --           --        (24,853)
                                                           ---------    ---------    ---------    ---------

NET INCOME                                                    14,315       12,118       82,344       36,372
                                                           ---------    ---------    ---------    ---------

PREFERRED STOCK DIVIDENDS                                        968          984        3,729        3,786
                                                           ---------    ---------    ---------    ---------

NET INCOME AFTER PREFERRED
        STOCK DIVIDENDS                                    $  13,347    $  11,134    $  78,615    $  32,586
                                                           =========    =========    =========    =========

</TABLE>

                                      -9-


<PAGE>

                     CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
                             STATEMENT OF CASH FLOWS
                                    UNAUDITED
                             (Thousands of Dollars)

<TABLE>
<CAPTION>

                                                         Three Months Ended
                                                              March 31,         
                                                          1999       1998
<S>                                                  <C>         <C>
Cash Flows From Operating:
   Net income                                          $ 14,315    $ 12,118
   Adjustments to reconcile net income to net cash
      provided by operating activities:
        Depreciation and amortization                    20,740      18,822
        Allowance for funds used during construction        (65)       (464)
        Deferred income taxes, net                       (4,975)     (4,497)
        Deferred investment tax credits, net               (621)       (834)
        Changes in assets and liabilities:
           Receivables, net                              (5,278)     21,184
           Materials and supplies                         8,657      (7,116)
           Accounts and wages payable                    (4,690)    (34,191)
           Taxes accrued                                  9,641       9,509
           Other, net                                    12,187      16,086
                                                       --------    --------
Net cash provided by operating activities                49,911      30,617

Cash Flows From Investing:
   Construction expenditures                            (22,075)    (15,273)
   Allowance for funds used during construction              65         464
                                                       --------    --------
Net cash used in investing activities                   (22,010)    (14,809)

Cash Flows From Financing:
   Dividends on common stock                            (17,155)    (17,155)
   Dividends on preferred stock                            (926)     (1,125)
   Redemptions -
      Short-term debt                                   (15,000)    (15,466)
      Long-term debt                                     (5,000)    (10,000)
   Issuances -
      Long-term debt                                       --        10,000
                                                       --------    --------
Net cash used in financing activities                   (38,081)    (33,746)

Net increase in cash and cash equivalents               (10,180)    (17,938)
Cash and cash equivalents at beginning of year           10,180      28,140
                                                       --------    --------
Cash and cash equivalents at end of period             $   --      $ 10,202
                                                       ========    ========

Cash paid during the periods:
   Interest (net of amount capitalized)                $  8,750    $ 10,086
   Income taxes, net                                   $    754    $    867
</TABLE>

                                      -10-

<PAGE>



CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
NOTES TO FINANCIAL STATEMENTS (UNAUDITED)
March 31, 1999


Note 1 - Central Illinois Public Service Company  (AmerenCIPS or the Registrant)
is a wholly-owned subsidiary of Ameren Corporation (Ameren), which is the parent
company of two utility  operating  companies,  the Registrant and Union Electric
Company  (AmerenUE).  Ameren is a registered  holding  company  under the Public
Utility  Holding  Company Act of 1935 (PUHCA)  formed in December  1997 upon the
merger of CIPSCO Incorporated (the Registrant's former parent) and AmerenUE (the
Merger).  Both  Ameren  Corporation  and its  subsidiaries  are  subject  to the
regulatory  provisions  of  the  PUHCA.  The  operating  companies  are  engaged
principally in the generation,  transmission,  distribution and sale of electric
energy and the purchase, distribution, transportation and sale of natural gas in
the states of Illinois and Missouri. Contracts among the companies--dealing with
jointly-owned generating facilities, interconnecting transmission lines, and the
exchange of electric  power--are  regulated  by the  Federal  Energy  Regulatory
Commission   (FERC)  or  the   Securities   and   Exchange   Commission   (SEC).
Administrative  support  services are provided to the  Registrant  by a separate
Ameren  subsidiary,  Ameren  Services  Company.  The  Registrant  serves 400,000
electric and 175,000 gas customers in a 20,000 square-mile region of central and
southern Illinois.

The Registrant also has a 20% interest in Electric Energy,  Inc. (EEI), which is
accounted  for under the equity method of  accounting.  EEI owns and operates an
electric generating and transmission facility in Illinois that supplies electric
power primarily to a uranium enrichment plant located in Paducah, Kentucky.

Note 2 - Financial  statement note  disclosures,  normally included in financial
statements prepared in conformity with generally accepted accounting principles,
have been omitted in this Form 10-Q pursuant to the Rules and Regulations of the
Securities and Exchange  Commission.  However, in the opinion of the Registrant,
the disclosures contained in this Form 10-Q are adequate to make the information
presented not misleading. See Notes to Financial Statements included in the 1998
Form 10-K for information relevant to the financial statements contained in this
Form 10-Q,  including  information as to the significant  accounting policies of
the Registrant.

Note 3 - In the opinion of the Registrant the interim financial statements filed
as part of this Form 10-Q  reflect all  adjustments,  consisting  only of normal
recurring  adjustments,  necessary  for a fair  statement of the results for the
periods presented. The Registrant's financial statements were prepared to permit
the information required in the Financial Data Schedule (FDS), Exhibit 27, to be
directly  extracted from the filed statements.  The FDS amounts correspond to or
are calculable  from the amounts  reported in the financial  statements or notes
thereto.

Note 4 - Due to the  effect of  weather  on sales and  other  factors  which are
characteristic of public utility  operations,  financial results for the periods
ended March 31, 1999 and 1998 are not  necessarily  indicative of trends for any
three-month or 12-month period.

Note 5 - In  conjunction  with the  Electric  Service  Customer  Choice and Rate
Relief Law of 1997,  a 5 percent  residential  electric  rate  decrease  for the
Registrant's electric customers was effective August 1, 1998. This rate decrease
is  expected to  decrease  electric  revenues  $11  million  annually,  based on
estimated levels of sales and assuming normal weather conditions. The Registrant
may be subject to additional 5 percent  residential  electric rate  decreases in
each of 2000 and 2002,  to the  extent  its rates  exceed  the  Midwest  utility
average at that time.  The  Registrant's  rates are currently  below the Midwest
utility average.

Note 6 - Statement of Position (SOP) 98-1, "Accounting for the Costs of Computer
Software  Developed or Obtained for Internal Use" became effective on January 1,
1999.  SOP 98-1  provides  guidance  on  accounting  for the  costs of  computer
software  developed or obtained for internal use. Under SOP 98-1, certain costs,
may be capitalized and amortized over some future period.  SOP 98-1 did not have
a  material  impact  on  the  Registrant's  financial  position  or  results  of
operations upon adoption.

                                      -11-

<PAGE>

The  Emerging  Issues Task Force of the  Financial  Accounting  Standards  Board
(EITF)  Issue  98-10,   "Accounting  for  Energy  Trading  and  Risk  Management
Activities" became effective on January 1, 1999. EITF 98-10 provides guidance on
the  accounting  for energy  contracts  entered into for the purchase or sale of
electricity,  natural  gas,  capacity  and  transportation.  The EITF  reached a
consensus in EITF 98-10 that sales and purchase  activities being performed need
to be classified as either  trading or  non-trading.  Furthermore,  transactions
that are determined to be trading  activities would be recognized on the balance
sheet measured at fair value,  with gains and losses included in earnings.  EITF
98-10  includes  factors  or  indicators  to  consider  when  determining  if  a
transaction is a trading or non-trading activity. Currently,  AmerenEnergy Inc.,
an energy marketing subsidiary of Ameren, enters into contracts for the sale and
purchase of energy on behalf of AmerenCIPS.  These  transactions  are considered
non-trading  activities  and are  accounted  for using the accrual or settlement
method, which represents industry practice.  Should any of AmerenEnergy's future
activities be considered trading activities based on the indicators  provided in
EITF 98-10, a change in accounting  practice  would be required.  EITF 98-10 did
not have a material impact on the Registrant's  financial position or results of
operations upon adoption.

Note 7 - Segment  information  for the three  month and 12 month  periods  ended
March 31, 1999 and 1998 is as follows:

<TABLE>
<CAPTION>

---------------------------------------------------------------------------------------------

(in millions)                                  Electric           Gas              Total
---------------------------------------------------------------------------------------------

<S>                                        <C>                  <C>               <C>  
Three months ended March 31, 1999:

Revenues                                     $  155               $ 53              $ 208
Operating Income (Net)                           20                  5                 25
---------------------------------------------------------------------------------------------

Three months ended March 31, 1998:

Revenues                                     $  150              $  50              $ 200
Operating Income (Net)                           19                  3                 22
---------------------------------------------------------------------------------------------

12 months ended March 31, 1999:

Revenues                                     $  728              $ 128              $ 856
Operating Income (Net)                          116                  7                123
---------------------------------------------------------------------------------------------

12 months ended March 31, 1998:

Revenues                                     $  690              $ 141              $ 831
Operating Income (Net)                           97                  5                102
---------------------------------------------------------------------------------------------

</TABLE>


Note 8 - Certain  reclassifications were made to prior-year financial statements
to conform to current-period presentation.

                                      -12-

<PAGE>


                           PART II. OTHER INFORMATION


ITEM 4.  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

         At the annual meeting of  stockholders  of the Registrant held on April
22, 1999,  the following  matter was presented to the meeting for a vote and the
results of such voting are as follows:

    Item (1)  Election of Directors.

                                                                       Non-Voted
              Name                          For          Withheld       Brokers 

    Paul A. Agathen...................  25,504,367           846            0
    Warner L. Baxter..................  25,504,367           846            0
    Donald E. Brandt..................  25,504,367           846            0
    Charles W. Mueller................  25,504,352           861            0
    Gary L. Rainwater.................  25,504,364           849            0


ITEM 6.  EXHIBITS AND REPORTS ON FORM 8-K

    (a)   Exhibits.

          Exhibit 12 -  Computation  of Ratio of Earnings to Fixed  Charges
          and Preferred Stock Dividend Requirements,  12 Months Ended March
          31, 1999.

          Exhibit 27 - Financial Data Schedule.

    (b)   Reports on Form 8-K.  None.


                                   SIGNATURES

         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/ Warner L. Baxter
                                                    ----------------------
                                                        Warner L. Baxter
                                                 Vice President and Controller
                                                (Principal Accounting Officer)


Date:  May 14, 1999

                                      -13-