Exhibit 5

Gowling Lafleur Henderson LLP
Barristers & Solicitors
Patent & Trade Mark Agents

[GRAPHIC OMITTED]

Incorporating the practice of SMITH LYONS


                                  June 30, 2003

ATI Technologies Inc.
1 Commerce Valley Drive East
Markham, Ontario
L3T 7X6

Ladies and Gentlemen:

          We  have  acted  as your  Canadian  counsel  in  connection  with  the
preparation of a Registration  Statement on Form S-8 to be filed with the United
States Securities and Exchange Commission on or about June 30, 2003 (as such may
thereafter be amended or supplemented, the "Registration Statement") relating to
the  registration by you of 10,000,000  Common Shares  ("Common  Shares") of ATI
Technologies Inc., a corporation  incorporated under the laws of the Province of
Ontario ("ATI"),  which may be issued in connection with options (the "Options")
granted pursuant to the ATI Technologies Inc. Share Option Plan (the "Plan"), in
the  manner  set  forth  in  the  Registration  Statement,  in  addition  to the
20,000,000 common shares previously  registered on Form S-8 under the Securities
Act of 1933, as amended (File Nos. 333-9576 and 333-13450).

          We have examined originals and copies,  certified or identified to our
satisfaction  of:  (i)  the  Registration  Statement,  (ii)  ATI's  Articles  of
Incorporation and By-Laws,  in each case, as amended,  (iii) certain resolutions
of ATI's  Board of  Directors  and (iv) such other  proceedings,  documents  and
records as we have deemed  relevant  or  necessary  as a basis for the  opinions
herein  expressed.  We have  assumed  the  genuineness  of all  signatures,  the
authenticity  of  all  documents  submitted  to us as  certified,  conformed  or
photostatic copies or facsimiles thereof.

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

1.        ATI has allotted and reserved the Common  Shares to be issued and sold
          upon the exercise of the Options.

2.        Upon the exercise of the Options and receipt by ATI of payment in full
          for the Common Shares, such Common Shares when sold as contemplated by
          the  Plan  will  be  duly  and  validly   issued  as  fully  paid  and
          non-assessable.

          We are  solicitors  qualified  to carry on the  practice of law in the
Province  of Ontario,  Canada only and we express no opinion as to any laws,  or
matters  governed  by any other  laws,  other than the laws of the  Province  of
Ontario and the federal laws of Canada applicable  therein.  We consent to being
named in the Registration Statement and the use of this opinion as an exhibit to
the Registration Statement.
                                               Yours very truly,

                                               /s/ Gowling Lafleur Henderson LLP



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