<SEC-DOCUMENT>0001144204-14-053681.txt : 20140902
<SEC-HEADER>0001144204-14-053681.hdr.sgml : 20140901
<ACCEPTANCE-DATETIME>20140902134750
ACCESSION NUMBER:		0001144204-14-053681
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20140901
FILED AS OF DATE:		20140902
DATE AS OF CHANGE:		20140902

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MDC PARTNERS INC
		CENTRAL INDEX KEY:			0000876883
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-ADVERTISING AGENCIES [7311]
		IRS NUMBER:				980364441
		STATE OF INCORPORATION:			A6
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		745 FIFTH AVENUE, 19TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10151
		BUSINESS PHONE:		646 429 1800

	MAIL ADDRESS:	
		STREET 1:		745 FIFTH AVENUE, 19TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10151

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MDC CORP INC
		DATE OF NAME CHANGE:	20001204

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MDC COMMUNICATIONS CORP
		DATE OF NAME CHANGE:	19961028

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MDC CORPORATION
		DATE OF NAME CHANGE:	19950419

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SENECAL LORI ANN
		CENTRAL INDEX KEY:			0001618269

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13718
		FILM NUMBER:		141077164

	MAIL ADDRESS:	
		STREET 1:		181 SULLIVAN STREET
		STREET 2:		PH
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10012
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>v386617_3.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2014-09-01</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000876883</issuerCik>
        <issuerName>MDC PARTNERS INC</issuerName>
        <issuerTradingSymbol>MDCA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001618269</rptOwnerCik>
            <rptOwnerName>SENECAL LORI ANN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MDC PARTNERS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>745 FIFTH AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10151</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO of The MDC Partner Network</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class A Subordinate Voting Shares</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>66331</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class A Restricted Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>87500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">&quot;Class A Restricted Stock&quot; means Class A Subordinate Voting Shares of the Issuer (hereinafter, &quot;Class A Shares&quot;) granted to the Reporting Person pursuant to Restricted Stock Grant Agreements dated as of November 1, 2013 and September 1, 2014 (the &quot;Grant Dates&quot;), respectively. The Restricted Stock will vest and the transfer restrictions shall lapse on the third anniversary of the applicable Grant Date (the &quot;Lapse Date&quot;), contingent upon certain events and the Reporting Person's continued service as Executive Officer of the Issuer until such Lapse Date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Lori Senecal</signatureName>
        <signatureDate>2014-09-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
