UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549



                                    FORM 8-K


                                 CURRENT REPORT




     Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934



                Date of Report (Date of earliest event reported):
                                  May 28, 2002





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




        Illinois                        1-3672                   37-0211380
(State or other jurisdiction          (Commission             (I.R.S. Employer
     of incorporation)                File Number)           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






ITEM 5.    OTHER EVENTS AND REGULATION FD DISCLOSURE

     Reference is made to Note 2 (Federal - Midwest ISO and Alliance RTO) to the
"Notes to Financial  Statements  (unaudited)" in Central Illinois Public Service
Company's  (AmerenCIPS) Form 10-Q for the quarterly period ended March 31, 2002,
for a discussion of the Federal Energy Regulatory  Commission's (FERC) April 25,
2002 order  requiring the Alliance  companies,  including us and our  affiliate,
Union  Electric  Company  (AmerenUE),   to  select  the  regional   transmission
organization (RTO) in which we will participate within thirty days of the order.
On May 28, 2002, we filed with the FERC  indicating  that we would return to the
Midwest  Independent  System Operator  (MISO),  although the exact nature of our
participation  (whether  as an  individual  transmission  owner  or  through  an
independent transmission company) is subject to further negotiations.  Until the
tariffs and other material terms of our  participation in the MISO are finalized
and approved by the FERC, we cannot predict the impact ongoing RTO  developments
will have on our future financial condition, results of operation or liquidity.


Safe Harbor Statement
- ---------------------

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 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    the  effects  of  participation  in  a  FERC-approved  RTO,  including
          activities associated with the MISO and the Alliance RTO; and
     o    legal and administrative proceedings.



                                    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
                                                          Controller
                                                  (Principal Accounting Officer)


Date:  May 30, 2002


                                       2