EXHIBIT 5


Barristers & Solicitors                          MCCARTHY TETRAULT LLP
Patent & Trade-mark Agents                       Suite 3300, 421-7th Avenue S.W.
                                                 Calgary AB T2P 4K9
                                                 Canada
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                                                 Facsimile: 403 260-3501
                                                 www.mccarthy.ca




November 22, 2002

TransAlta Corporation
110-12th Avenue S.W.
Box 1900, Station M
Calgary, Alberta T2P 2M1

Dear Gentlemen:

RE:  TRANSALTA CORPORATION
     REGISTRATION STATEMENT ON FORM S-8

We are counsel to TransAlta Corporation (the "Corporation"), a corporation
incorporated under the Canada Business Corporations Act.

We refer to the filing by the Corporation of the above-captioned Registration
Statement on Form S-8 (the "Registration Statement") under the Securities Act
of 1933, as amended, covering the registration of an aggregate of 1,500,000
common shares without par value of the Corporation (the "Shares"), together
with attached common share purchase rights (the "Rights"), issuable by the
Corporation as described in the Registration Statement. The terms of the
Rights are set forth in the Shareholder Rights Plan Agreement dated as of
October 13, 1992, as amended and restated as of November 26, 1992, May 14,
1998 and May 3, 2001 (the "Rights Agreement") between the Corporation and
CIBC Mellon Trust Company, as Rights Agent.

We have examined the Articles of the Corporation, resolutions of the Board of
Directors of the Corporation in respect of the issuance of the Shares and
original, reproduced or certified copies of such records of the Corporation
and such agreements, certificates of public officials, certificates of
officers and representatives of the Corporation and others, and such other
documents, papers, statutes and authorities as we deem necessary to form the
basis of the opinions hereinafter expressed. In such examination, we have
assumed the genuineness of all signatures and the conformity to original
documents of all documents supplied to us as copies. As to various questions
of fact material to such opinions, we have relied upon the records of the
Corporation and upon statements and certificates of officers and
representatives of the Corporation and others.

Based on and subject to the foregoing, we are of the opinion that:

1.   The Shares have been duly authorized, and, when issued in accordance
     with the TransAlta Corporation Stock Option Plan, as amended, referred
     to in the Registration Statement, will be legally issued by the
     Corporation as fully paid and non-assessable shares in the capital of
     the Corporation.


        VANCOUVER, CALGARY, LONDON, TORONTO, OTTAWA, MONTREAL, QUEBEC,
                        NEW YORK AND LONDON, ENGLAND



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2.   The Rights associated with the Shares referred to in paragraph 1 will be
     legally issued when (i) such Rights have been duly issued in accordance
     with the terms of the Rights Agreement and (ii) the associated Shares
     have been duly issued as set forth in paragraph 1.

We hereby consent to your filing a copy of this Opinion as an exhibit to said
Registration Statement and to all references to our firm included in or made
part of the Registration Statement.

Yours very truly,

MCCARTHY TETRAULT LLP
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