<PAGE>                           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):
                                January 11, 2001





                     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


<PAGE>


ITEM 5.         OTHER EVENTS AND REGULATION FD DISCLOSURE

Reference is made to Management's Discussion and Analysis of Financial Condition
and Results of Operations  under the caption  "Midwest ISO" and to Note 6 of the
Notes to Financial  Statements in the  Registrant's  Form 10-Q for the quarterly
period ended September 30, 2000, for a discussion of the Registrant's  intention
to withdraw from the Midwest  Independent System Operator (MISO) and to become a
member of the Alliance Regional Transmission Organization (Alliance RTO).

In the fourth quarter of 2000, the Registrant recorded a $8 million nonrecurring
charge ($5 million after income taxes),  as a result of its decision to withdraw
from the MISO.  This charge  relates to the  Registrant's  estimated  obligation
under the MISO agreement for costs incurred by the MISO.

On January 11,  2001,  the  Registrant  signed an agreement to join the Alliance
RTO.  Regional   transmission   organizations,   including   independent  system
operators, are entities that ensure comparable and non-discriminatory  access to
regional electric transmission systems.  Following the announcements of Illinois
Power and Commonwealth Edison of their intent to withdraw from the MISO and join
the Alliance RTO, the Registrant  determined that the operational  configuration
of the MISO was  unacceptable and announced its withdrawal in November 2000. The
Registrant  decided to withdraw to ensure the  continued  reliable and efficient
operation of the Registrant's  transmission system. The Registrant's  withdrawal
from the MISO and its  membership  in the Alliance RTO are subject to regulatory
approvals.

SAFE HARBOR STATEMENT

The foregoing estimates of the Registrant's  obligation under the MISO agreement
for costs  incurred  by the MISO are  "forward-looking"  statements  within  the
meaning of the "Safe  Harbor"  provisions of the Private  Securities  Litigation
Reform Act of 1995. Such statements  involve risks and uncertainties  that could
cause actual  results to differ  materially  from those  discussed  herein.  The
following  factors  could cause  results to differ  materially  from  management
expectations  as suggested by such  forward-looking  statements:  the effects of
regulatory actions,  including changes in regulatory policy; changes in laws and
other  governmental  actions;  business and economic  conditions;  and 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/ Warner L. Baxter
                                    --------------------------------------------
                                                      Warner L. Baxter
                                            Vice President and Controller
                                            (Principal Accounting Officer)
Date:  January 12, 2001
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{"company-data": {"conformed-name": "CENTRAL ILLINOIS PUBLIC SERVICE CO", "cik": "0000018654", "assigned-sic": "4931", "irs-number": "370211380", "state-of-incorporation": "IL", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "001-03672", "film-number": "1507620"}, "business-address": {"street1": "607 E ADAMS ST", "city": "SPRINGFIELD", "state": "IL", "zip": "62739", "phone": "3145543356"}, "mail-address": {"street1": "CENTRAL ILLINOIS PUBLIC SERVICE CO", "street2": "607 E ADAMS ST", "city": "SPRINGFIELD", "state": "IL", "zip": "62739"}}
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):
                                January 11, 2001

                     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 Management's Discussion and Analysis of Financial Condition
and Results of Operations  under the caption  "Midwest ISO" and to Note 6 of the
Notes to Financial  Statements in the  Registrant's  Form 10-Q for the quarterly
period ended September 30, 2000, for a discussion of the Registrant's  intention
to withdraw from the Midwest  Independent System Operator (MISO) and to become a
member of the Alliance Regional Transmission Organization (Alliance RTO).

In the fourth quarter of 2000, the Registrant recorded a $8 million nonrecurring
charge ($5 million after income taxes),  as a result of its decision to withdraw
from the MISO.  This charge  relates to the  Registrant's  estimated  obligation
under the MISO agreement for costs incurred by the MISO.

On January 11,  2001,  the  Registrant  signed an agreement to join the Alliance
RTO.  Regional   transmission   organizations,   including   independent  system
operators, are entities that ensure comparable and non-discriminatory  access to
regional electric transmission systems.  Following the announcements of Illinois
Power and Commonwealth Edison of their intent to withdraw from the MISO and join
the Alliance RTO, the Registrant  determined that the operational  configuration
of the MISO was  unacceptable and announced its withdrawal in November 2000. The
Registrant  decided to withdraw to ensure the  continued  reliable and efficient
operation of the Registrant's  transmission system. The Registrant's  withdrawal
from the MISO and its  membership  in the Alliance RTO are subject to regulatory
approvals.

SAFE HARBOR STATEMENT

The foregoing estimates of the Registrant's  obligation under the MISO agreement
for costs  incurred  by the MISO are  "forward-looking"  statements  within  the
meaning of the "Safe  Harbor"  provisions of the Private  Securities  Litigation
Reform Act of 1995. Such statements  involve risks and uncertainties  that could
cause actual  results to differ  materially  from those  discussed  herein.  The
following  factors  could cause  results to differ  materially  from  management
expectations  as suggested by such  forward-looking  statements:  the effects of
regulatory actions,  including changes in regulatory policy; changes in laws and
other  governmental  actions;  business and economic  conditions;  and 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/ Warner L. Baxter
                                    --------------------------------------------
                                                      Warner L. Baxter
                                            Vice President and Controller
                                            (Principal Accounting Officer)
Date:  January 12, 2001