Exhibit 99.1


[GRAPHIC OMITTED][GRAPHIC OMITTED]
                                                                One Ameren Plaza
                                                            1901 Chouteau Avenue
                                                             St. Louis, MO 63103
Contact:

Media                  Analysts                                Investors
Tim Fox                Bruce Steinke                           Investor Services
(314) 554-3120         (314) 554-2574                          invest@ameren.com
tfox2@ameren.com       bsteinke@ameren.com

FOR IMMEDIATE RELEASE
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                          AMEREN REPORTS 2003 EARNINGS


     St.  Louis,  Mo.,  Feb. 10,  2004---Ameren  Corporation  (NYSE:  AEE) today
announced 2003 net income of $524 million,  or $3.25 per share ($3.25  diluted),
compared to net income of $382 million,  or $2.61 per share ($2.60 diluted),  in
2002. Ameren recorded net income of $38 million, or 24 cents per share (24 cents
diluted), for the fourth quarter of 2003, compared to a net loss of $32 million,
or 20 cents per share (20 cents diluted), for the fourth quarter of 2002.

     Net income in 2003 included a third quarter  after-tax gain of $31 million,
or 19 cents per share,  related to the settlement of a dispute over certain mine
reclamation  issues with a coal supplier and a first quarter  after-tax  gain of
$18  million,  or 11 cents per share,  due to the  adoption of a new  accounting
standard related to the recognition of asset retirement obligations.  Net income
in 2002 included a fourth quarter  after-tax charge of $58 million,  or 40 cents
per share,  which primarily related to a voluntary  employee  retirement program
and  restructuring  charges  associated  with the  retirement  of the  company's
Venice, Ill., plant.

     Excluding  these  items,  adjusted  (non-GAAP)  net income in 2003 was $475
million, or $2.95 per share ($2.95 diluted), compared to adjusted (non-GAAP) net
income of $440 million,  or $3.01 per share ($3.00 diluted),  in 2002.  Adjusted
(non-GAAP)  net  income for the fourth  quarter of 2002 was $26  million,  or 18
cents per share (18 cents diluted).

     "Despite our share of challenges in 2003, we again  delivered solid returns
to our  shareholders  and  reliable  service  to our  customers,"  said  Gary L.
Rainwater,  chairman and chief executive officer of Ameren  Corporation.  "As we
began 2003, we faced a weak economy and energy market,  electric rate reductions
in our Missouri  service  territory and rising employee benefit costs. To tackle
these  challenges,  we  initiated a voluntary  retirement  program  that reduced
staffing levels; we closed inefficient generating units and took steps to reduce
employee benefit costs,  while still  maintaining our position as an employer of
choice."

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     Mr. Rainwater added, "In the spring of 2003, an unexpected  challenge arose
as the worst  series of storms  and  tornados  in our  history  hit our  service
territory. However, our crews persevered and restored service quickly. Following
the outages our customer service and satisfaction ratings actually  increased--a
testament  to the hard work and the  positive  impression  our  crews  made with
customers."

     "As we moved  through 2003, we  seamlessly  completed the  acquisition  and
integration  of CILCORP Inc. As a result,  we realized  anticipated  acquisition
synergies  and fully expect to realize  even  greater  synergies in the future,"
noted Mr.  Rainwater.  "Lastly,  our cost  containment  measures  and  excellent
operating performance, when combined with better-than-expected power prices, put
us in a position to offset lower sales due to mild weather."

     Electric revenues in 2003 increased by $417 million,  compared to 2002. The
acquisition of CILCORP Inc.  (including its utility  subsidiary now operating as
AmerenCILCO)  increased  electric revenues by $497 million.  Higher  interchange
revenues  associated  with higher power prices and the improved  availability of
power plants also increased electric revenues by approximately $80 million. As a
result,  earnings from interchange power sales by AmerenEnergy,  Inc., on behalf
of AmerenUE  and  AmerenEnergy  Generating  Company,  were 55 cents per share in
2003, versus 20 cents per share in 2002.

     These  increases in revenues were  partially  offset by lower revenues from
native load customers due to cooler summer  weather in 2003,  compared to hotter
than normal summer  weather in 2002.  The company  estimates that milder weather
resulted in a 40 to 50 cent per share reduction in 2003 net income,  compared to
2002. In addition,  electric rate  reductions  in  AmerenUE's  Missouri  service
territory  lowered  2003  revenue by $34  million,  as compared to 2002.  In the
company's pre-CILCORP  acquisition service area,  weather-sensitive  residential
and  commercial  electric  kilowatthour  sales declined 4 percent and 2 percent,
respectively,   in  2003,  compared  to  2002.   However,   industrial  electric
kilowatthour  sales in 2003  increased  2 percent in the  company's  pre-CILCORP
acquisition service territory.

     Other  operations and maintenance  expenses  increased $64 million in 2003,
compared  to  2002.  Increased  expenses  due to the  acquisition  of  CILCORP's
operations  ($135  million) and rising  employee  benefit  costs were  partially
offset by lower labor costs  resulting  from the  voluntary  retirement  program
implemented  at  Ameren  in  early  2003 and  lower  electric  generating  plant
maintenance costs. Earnings per share were also unfavorably  impacted,  compared
to 2002, by higher depreciation expenses and financing costs associated with

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increased  capital  expenditures,  as well as a greater  number of common shares
outstanding  resulting  from  shares  issued  in 2002  and  2003 as the  company
continued to maintain its strong credit profile.

     As noted previously, Ameren completed the acquisition of CILCORP in January
2003, and completed the  integration  of financial and operating  systems in the
second half of 2003.  During  2003,  the CILCORP  transaction  was  accretive to
earnings  per  share  by   approximately  4  cents,   consistent  with  Ameren's
expectations.

     On February 3, 2004, Ameren announced the signing of a definitive agreement
to purchase the stock of Decatur,  Ill.-based  Illinois  Power  Company and a 20
percent interest in Electric Energy,  Inc. (EEI) from Dynegy Inc. (NYSE: DYN) in
a transaction  valued at $2.3 billion.  Ameren also announced that its financing
plan for this transaction would include the issuance of new Ameren common stock,
which in total,  is  expected  to equal at least 50 percent  of the  transaction
value. Last week, Ameren sold  approximately 19.1 million shares of common stock
valued at $875  million.  The net proceeds  from the offering are expected to be
ultimately used for this acquisition.

     "Consistent  with our  acquisition  of CILCORP,  we intend to approach  our
financing  for the Illinois  Power  acquisition  in a  conservative  and prudent
fashion," said Warner L. Baxter,  executive  vice president and chief  financial
officer.  "We view our  acquisition  of Illinois  Power and a greater  ownership
interest in EEI as a strategic long-term investment, which calls for a financing
plan consistent with this perspective."

     Mr. Baxter added,  "We expect this  acquisition to be accretive to earnings
by 5 to 10 cents per share in each of the first two years  after  closing and to
provide significant  long-term value for all of our stakeholders.  However, last
week's issuance of common stock prior to the closing of the acquisition  will be
dilutive to 2004 earnings per share by approximately 15 to 18 cents,  assuming a
year-end closing of the transaction."

     As a result of the issuance of the 19.1 million new shares of common stock,
Ameren  announced today that it now expects its 2004 earnings per share to range
between  $2.75 and $2.95 per  share.  Prior to the  issuance  of the new  common
stock,  the company  expected its 2004  earnings  per share would range  between
$2.90 and $3.10 per share.  The 2004 estimate  excludes any  potential  earnings
impact of the  Illinois  Power  acquisition  or potential  further  common stock
issuances  prior to the closing of the  transaction.  The company's  guidance is
subject to, among other things,  plant operations,  weather  conditions,  energy
market and

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economic  conditions,  unusual or otherwise unexpected gains or losses and other
risks and  uncertainties  outlined in the company's  Forward-Looking  Statements
section of this release.

     Ameren will conduct a conference  call for financial  analysts at 9:00 a.m.
(Central  Time) on Tuesday,  Feb. 10, to discuss 2003 net income and the updated
2004  guidance.  Investors,  the news  media and the public may listen to a live
Internet  broadcast of the Ameren analyst call at  www.ameren.com by clicking on
"2003 Earnings  Conference  Call," then the appropriate  audio link. The analyst
call will also be available  for replay on the Internet for one year.  Telephone
playback of the conference  call will also be available  beginning at 12:00 p.m.
(Central  Time),  Feb.  10,  until Feb.  17 by  dialing,  U.S.  (800)  428-6051;
international (973) 709-2089, and entering the number: 331947.

     With  assets  of $14.3  billion,  Ameren  owns a  diverse  mix of  electric
generating plants strategically located in its Midwest market with a capacity of
more than 14,700  megawatts.  Ameren serves 1.7 million  electric  customers and
500,000  natural gas  customers  in a 49,000  square-mile  area of Missouri  and
Illinois.

Forward-Looking Statements
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     Statements made in this release,  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, the company is 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 release and in past and subsequent
securities  filings,  could  cause  actual  results  to differ  materially  from
management expectations as suggested by such "forward-looking" statements:

o    the closing and timing of Ameren's  acquisition  of Illinois  Power and the
     impact of any  conditions  imposed by regulators  in connection  with their
     approval thereof;
o    the effects of the  stipulation  and  agreement  relating  to the  AmerenUE
     Missouri  electric  excess  earnings  complaint  case and other  regulatory
     actions, including changes in regulatory policy;
o    changes in laws and other  governmental  actions,  including  monetary  and
     fiscal policy;
o    the impact on the company 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 the company's  business at both
     the state and federal levels;
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    the  availability of fuel for the production of  electricity,  such as coal
     and natural gas, and purchased power and natural gas for distribution,  and
     the level and  volatility  of future  market  prices for such  commodities,
     including the ability to recover any increased costs;
o    the use of financial and derivative instruments;
o    average rates for electricity in the Midwest;
o    business and economic conditions;
o    the impact of the adoption of new accounting  standards and the application
     of appropriate technical accounting rules and guidance;
o    interest rates and the availability of capital;
o    actions of  ratings  agencies  and the  effects  of such  actions;  weather
     conditions;  generation plant  construction,  installation and performance;
     operation of nuclear power facilities and decommissioning costs;
o    the  effects  of  strategic   initiatives,   including   acquisitions   and
     divestitures;
o    the impact of current environmental regulations on utilities and generating
     companies 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  benefits costs,  including changes in returns on
     benefit plan assets;
o    disruptions  of the capital  markets or other events  making the  company's
     access to necessary capital more difficult or costly;
o    competition from other generating facilities, including new facilities that
     may be developed;  difficulties  in  integrating  AmerenCILCO  and Illinois
     Power with the company's other businesses;
o    changes in the coal markets,  environmental  laws or regulations,  or other
     factors  adversely  impacting  synergy  assumptions in connection  with the
     CILCORP Inc. and Illinois Power acquisitions;
o    cost and availability of transmission  capacity for the energy generated by
     the company's  generating  facilities  or required to satisfy  energy sales
     made by the company; and legal and administrative proceedings.

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