-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 WZMvkMq/Lwaajnzgg2b14ocnu2ce3iebpz0s9N3Sng31ZiriQk7WV47DwweK3OP9
 Qhk8Y7dCJXHginIokhRb2g==

<SEC-DOCUMENT>0001135971-11-000008.txt : 20110126
<SEC-HEADER>0001135971-11-000008.hdr.sgml : 20110126
<ACCEPTANCE-DATETIME>20110126101148
ACCESSION NUMBER:		0001135971-11-000008
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20110124
FILED AS OF DATE:		20110126
DATE AS OF CHANGE:		20110126

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FRIEL PAUL W
		CENTRAL INDEX KEY:			0001464297

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31403
		FILM NUMBER:		11548155

	MAIL ADDRESS:	
		STREET 1:		701 NINTH STREET NW
		CITY:			WASHINGTON
		STATE:			DC
		ZIP:			20068

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PEPCO HOLDINGS INC
		CENTRAL INDEX KEY:			0001135971
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC & OTHER SERVICES COMBINED [4931]
		IRS NUMBER:				522297449
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		SUITE 1300
		STREET 2:		701 NINTH STREET, NW
		CITY:			WASHINGTON
		STATE:			DC
		ZIP:			20068
		BUSINESS PHONE:		202-872-2000

	MAIL ADDRESS:	
		STREET 1:		SUITE 1300
		STREET 2:		701 NINTH STREET, NW
		CITY:			WASHINGTON
		STATE:			DC
		ZIP:			20068

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NEW RC INC
		DATE OF NAME CHANGE:	20010302
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-01-24</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001135971</issuerCik>
        <issuerName>PEPCO HOLDINGS INC</issuerName>
        <issuerTradingSymbol>POM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001464297</rptOwnerCik>
            <rptOwnerName>FRIEL PAUL W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>701 NINTH STREET NW</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20068</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP &amp; General Auditor</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9054</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By 401-k plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By spouse</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2011-01-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>347</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>18.54</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15267</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>Paul W. Friel by Ellen S. Rogers, Attorney-in-Fact</signatureName>
        <signatureDate>2011-01-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----