Exhibit 99.1


[GRAPHIC OMITTED][GRAPHIC OMITTED]
                                                        Ameren Services
                                                        101 Madison/P.O. Box 780
                                                        Jefferson City, MO 65102

Contacts:


Media:                            Analysts:                    Investors:
Mike Cleary                       Bruce Steinke                Investor Services
(573) 681-7137                    (314) 554-2574               invest@ameren.com
mcleary@ameren.com                bsteinke@ameren.com

FOR IMMEDIATE RELEASE
- ---------------------

           AMERENUE SEEKS NATURAL GAS RATE INCREASE; PROPOSES PHASE-IN

                AND OTHER PROVISIONS TO MINIMIZE CUSTOMER IMPACT

     JEFFERSON CITY, MO., May 23,  2003--Citing  significant  investments in the
energy  infrastructure  of its  gas  business  and  rising  operating  expenses,
AmerenUE, an operating company of Ameren Corporation  (NYSE:AEE),  today filed a
request with the Missouri Public Service  Commission (PSC) for a phased-in $26.7
million  increase in natural gas delivery  rates for its  approximately  111,000
Missouri gas  customers.  In the filing,  AmerenUE notes that this would be only
the third increase in the company's  Missouri gas delivery rates since 1987. The
request will not have any immediate  effect on customers' gas bills,  as it must
first go through the process of PSC review and hearings.

     To minimize the impact on customers,  AmerenUE is proposing to phase in the
new rates over two years,  with one half of the increase  taking  effect Dec. 1,
2003 and the other half taking  effect Nov. 1, 2004.  AmerenUE  would also agree
not to  seek  additional  increases  in  gas  delivery  rates  through  Nov.  1,
2006--excluding   any   special   provisions   for  the   recovery   of  certain
infrastructure  costs that may be provided by law.

     The proposal also calls for the company to contribute  $1.75 million to its
Dollar More energy  assistance  program to help  low-income  customers pay their
utility bills,  with the first $1 million  contribution set for Dec. 1, 2003 and
$250,000 in each of the following three years.  When coupled with the $9 million
commitment  to Dollar More that  AmerenUE made as part of its electric rate case
settlement  in 2002,  the  company  will have  committed  $10.75  million in new
support for this important energy assistance program in the last year.  AmerenUE
notes that these  contributions will not be recovered in its electric or natural
gas rates.

                                    * more *




first add

     "Our  innovative  rate proposal  mitigates the impact of increased rates on
customers' bills,  particularly  low-income  customers,  while it permits timely
recovery of critical energy infrastructure investments," says AmerenUE President
and Chief  Operating  Officer Gary L.  Rainwater.  "This  proposal  balances the
interests of all stakeholders  and will ensure continued  reliability and strong
service to all of our natural gas customers."

     In the filing,  the company is seeking to recover expenses  associated with
more than $50  million  of  investments  in gas system  improvements,  including
significant  replacement of cast iron mains and unprotected  steel service lines
as well as costs  for  customer  service  system  improvements  that  have  been
completed  since the last  rate  case.

     Thomas R. Voss,  AmerenUE senior vice president for Energy  Delivery,  says
that since May 1, 2000, the company has replaced about 55 miles of old cast iron
pipes and more than 3,000 service lines with modern,  more durable  polyethylene
pipe,  largely to comply with state  regulations.  "In  addition,  we have added
about 142 miles of new gas mains and more  than  7,000  service  connections  to
accommodate  new growth,"  Voss says.  "AmerenUE  customers  are  receiving  the
benefits  of these  expenditures,  but our current  rates do not  reflect  these
higher costs."

     The  requested  rate change would result in an overall  increase of about 9
percent in customers'  natural gas costs  beginning  Dec. 1, 2003, and another 9
percent beginning Nov. 1, 2004. With the completion of this phase-in period, the
net increase in an average  monthly  residential gas bill would be about $16.26,
compared to current  bills.

     This amount does not  include any changes  that may occur in the  Purchased
Gas  Adjustment  (PGA),  which  reflects  the  commodity  cost of gas  from  the
company's suppliers.  Supplier costs are not regulated,  and go up or down based
on supply and demand without  "mark-up" by AmerenUE.

     Gas  delivery  rates  reflect  the  cost  of  constructing,  operating  and
maintaining  the company's  natural gas system.  These costs usually account for
about a third of a typical residential  customer's total gas bill, while the PGA
accounts for the rest, excluding taxes.

                                    * more *




second add

     Changes in AmerenUE's Missouri PGA factor usually occur twice a year, while
the company's gas delivery rates have not changed since Nov. 1, 2000.

     To help customers  control their energy costs,  Ameren  provides a range of
energy-saving  tips on its Web  site:  www.ameren.com.  AmerenUE  also  offers a
Budget  Billing  Plan that  enables  customers  to  minimize  the impact of rate
changes and big seasonal  changes in energy use by spreading  their energy costs
out over the entire year.  Customers can sign up for Budget Billing  through the
Ameren Web site or by calling 1-800-55-ASK-UE (1-800-552-7583).

     AmerenUE is a subsidiary  of St.  Louis-based  Ameren  Corporation.  Ameren
companies serve 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

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,  AmerenUE is providing this
cautionary  statement  to identify  important  factors  that could cause  actual
results to differ  materially  from those  anticipated.  The factors,  discussed
elsewhere in this release and in  AmerenUE's  annual report on SEC Form 10-K for
the fiscal year ended  December 31, 2002,  and  subsequent  securities  filings,
could  cause  results to differ  materially  from  management  expectations,  as
suggested by such "forward-looking" statements.