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                                    FORM 6-K
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                            REPORT OF FOREIGN ISSUER
                      PURSUANT TO RULE 13a-16 OR 15d-16 OF
                      THE SECURITIES EXCHANGE ACT OF 1934


                           For the month of May 2003


                          COMMISSION FILE NO. 1-8887


                         TRANSCANADA PIPELINES LIMITED
                 (TRANSLATION OF REGISTRANT'S NAME INTO ENGLISH)


              450 - 1 STREET S.W., CALGARY, ALBERTA, T2P 5H1, CANADA
                     (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)


(Indicate by check mark whether the registrant files or will file annual
reports under cover of Form 20-F or Form 40-F)

        Form 20-F                       Form 40-F        X
                   -------------                   -------------

(Indicate by check mark whether the registrant by furnishing the information
contained in this Form is also thereby furnishing the information to the
Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of
1934.)

        Yes                             No               X
                   -------------                   -------------

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A copy of TransCanada Corporation's News Release dated May 15, 2003 announcing
that a Plan of Arrangement between TransCanada Corporation and TransCanada
PipeLines Limited became effective is furnished herewith as Exhibit "1".


                                 SIGNATURES

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.


                                     TRANSCANADA PIPELINES LIMITED



                                     By: /s/ Rhondda E.S. Grant
                                         --------------------------------------
                                         Rhondda E.S. Grant
                                         Vice-President and Corporate Secretary


May 27, 2003
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                                  EXHIBIT INDEX

1.    News Release of TransCanada Corporation dated May 15, 2003 entitled
      "TransCanada Corporation Arrangement Effective Today".

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