Exhibit 8.3



February 13, 2003

Moore Corporation Limited
6100 Vipond Drive
Mississauga, Ontario
L5T 2X1

Ladies and Gentlemen:

MOORE CORPORATION LIMITED
REGISTRATION STATEMENT ON FORM S-4

We have acted as Canadian counsel to Moore Corporation Limited, a Canadian
corporation (the "Company"), in connection with (i) the proposed merger (the
"Merger") of M-W Acquisition, Inc., a Delaware corporation, with and into
Wallace Computer Services, Inc., a Delaware corporation ("Wallace"), followed by
a merger of the surviving corporation of the Merger with and into another
subsidiary of the Company (the "Subsequent Merger"), if Sullivan & Cromwell LLP
deliver to the Company and Sidley Austin Brown & Wood delivers to Wallace an
opinion to the effect that, among other things, the Merger and the Subsequent
Merger, taken together, will constitute a reorganization under Section 368(a) of
the Internal Revenue Code of 1986, as amended, and (ii) the Registration
Statement on Form S-4 (the "Registration Statement") filed by the Company with
the Securities and Exchange Commission under the Securities Act of 1933, as
amended (the "Securities Act"), on the date hereof.

We hereby confirm to you that the views set forth under the heading
"Taxation-Certain Canadian Federal Income Tax Considerations" in the proxy
statement-prospectus forming a part of the Registration Statement are our
opinion, subject to the limitations set forth therein.

We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to us under the heading "Taxation"
in the proxy statement/prospectus therein. In giving such consent, we do not
thereby admit that we are in the category of persons whose consent is required
under Section 7 of the Securities Act or the rules and regulations promulgated
thereunder, or that we are "experts" within the meaning of the Securities Act or
the rules and regulations promulgated thereunder.

Yours very truly,



OSLER, HOSKIN & HARCOURT LLP