-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 CE/yRx6DP2pLVvv4ekv4/LXKfg/wk8YZYAhC6ex1EsDzWWlqdYiXo7LirzmF81sk
 jpW8Ia78XNS7VjvRO86pOw==

<SEC-DOCUMENT>0000018654-04-000005.txt : 20040311
<SEC-HEADER>0000018654-04-000005.hdr.sgml : 20040311
<ACCEPTANCE-DATETIME>20040311085520
ACCESSION NUMBER:		0000018654-04-000005
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030422
FILED AS OF DATE:		20040311

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LIDDY RICHARD A
		CENTRAL INDEX KEY:			0001184482

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-03672
		FILM NUMBER:		04661762

	BUSINESS ADDRESS:	
		STREET 1:		GENAMERICA
		STREET 2:		700 MARKET ST
		CITY:			ST LOUIS
		STATE:			MO
		ZIP:			63101

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CENTRAL ILLINOIS PUBLIC SERVICE CO
		CENTRAL INDEX KEY:			0000018654
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC & OTHER SERVICES COMBINED [4931]
		IRS NUMBER:				370211380
		STATE OF INCORPORATION:			IL
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		607 E ADAMS ST
		CITY:			SPRINGFIELD
		STATE:			IL
		ZIP:			62739
		BUSINESS PHONE:		3145543356

	MAIL ADDRESS:	
		STREET 1:		CENTRAL ILLINOIS PUBLIC SERVICE CO
		STREET 2:		607 E ADAMS ST
		CITY:			SPRINGFIELD
		STATE:			IL
		ZIP:			62739
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2003-04-22</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000018654</issuerCik>
        <issuerName>CENTRAL ILLINOIS PUBLIC SERVICE CO</issuerName>
        <issuerTradingSymbol>CIP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001184482</rptOwnerCik>
            <rptOwnerName>LIDDY RICHARD A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P. O. BOX 66149, MC-1370</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ST. LOUIS</rptOwnerCity>
            <rptOwnerState>MO</rptOwnerState>
            <rptOwnerZipCode>63166-6149</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>No securities to report</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>G. L. Waters, Asst. Secy. for Richard A. Liddy</signatureName>
        <signatureDate>2004-03-11</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----