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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,
 UZp/4XhryILdl2VSvGLR3ei+AmEmiqhg1AzL/vJQ6ueGxnzcc0FC8U4M0rj+ucC2
 FjR2vjY3n1H3KuuE1LAteQ==

<SEC-DOCUMENT>0001263291-06-000001.txt : 20060808
<SEC-HEADER>0001263291-06-000001.hdr.sgml : 20060808
<ACCEPTANCE-DATETIME>20060808182218
ACCESSION NUMBER:		0001263291-06-000001
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20060612
FILED AS OF DATE:		20060808
DATE AS OF CHANGE:		20060808

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TC PIPELINES LP
		CENTRAL INDEX KEY:			0001075607
		STANDARD INDUSTRIAL CLASSIFICATION:	NATURAL GAS TRANSMISSION [4922]
		IRS NUMBER:				522135448
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		110 TURNPIKE ROAD SUITE 203
		CITY:			WESTBOROUGH
		STATE:			MA
		ZIP:			01581
		BUSINESS PHONE:		5088717046

	MAIL ADDRESS:	
		STREET 1:		110 TURNPIKE RD
		STREET 2:		SUITE 203
		CITY:			WESTBOROUGH
		STATE:			MA
		ZIP:			01581

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Zimmerman Mark A P
		CENTRAL INDEX KEY:			0001372012

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-26091
		FILM NUMBER:		061014504

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		(403) 920-2501

	MAIL ADDRESS:	
		STREET 1:		450-1ST STREET SW
		CITY:			CALGARY
		STATE:			A0
		ZIP:			T2P 5H1
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2006-06-12</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001075607</issuerCik>
        <issuerName>TC PIPELINES LP</issuerName>
        <issuerTradingSymbol>TCLP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001372012</rptOwnerCik>
            <rptOwnerName>Zimmerman Mark A P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450-1ST STREET SW</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CALGARY</rptOwnerCity>
            <rptOwnerState>A0</rptOwnerState>
            <rptOwnerZipCode>T2P 5H1</rptOwnerZipCode>
            <rptOwnerStateDescription>ALBERTA, CANADA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP, Business Development</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <ownerSignature>
        <signatureName>/s/ Donald J. DeGrandis, Attorney for Mark AP Zimmerman</signatureName>
        <signatureDate>2006-08-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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