Exhibit 5.1


                   [Osler, Hoskin & Harcourt LLP Letterhead]


                                                               February 13, 2002





Moore Corporation Limited
c/o Moore Executive Offices
One Canterbury Green
Stamford, Connecticut
U.S.A.  06901

Ladies and Gentlemen:


MOORE CORPORATION LIMITED
REGISTRATION STATEMENT ON FORM S-3

We have acted as Canadian counsel to Moore Corporation Limited (the "Company")
in connection with the filing with the Securities and Exchange Commission of the
Company's Registration Statement on Form S-3 (the "Registration Statement")
under the Securities Act of 1933, as amended (the "Securities Act"), relating to
the registration of 18,234,525 common shares of the Company (the "Shares") to be
sold by certain shareholders of the Company.

For the purposes of expressing the opinion set forth herein, we have examined
originals or copies, certified or otherwise identified to our satisfaction, of
the articles of incorporation and the by-laws of the Company, each as amended
from time to time, and resolutions of the directors of the Company with respect
to the matters referred to herein. We have also examined such certificates of
public officials, officers of the Company, corporate records and other documents
as we have deemed relevant or necessary as a basis for the opinion expressed
below. In our examination of such documents, we have assumed the authenticity of
all documents submitted to us as certified copies or facsimiles thereof.

We are barristers and solicitors qualified to practice law in the Province of
Ontario and our opinion expressed below is limited to the laws of such Province
and the laws of Canada applicable therein and should not be relied upon, nor is
it given, in respect of the laws of any other jurisdiction.

Based upon and subject to the foregoing, we are of the opinion that the Shares
are validly issued, fully paid and non-assessable shares of the Company.

We hereby consent to the use of this opinion as an exhibit to the Registration
Statement and to the use of our name under the caption "Validity of Common
Shares" in the Prospectus forming a part of the Registration Statement. In
giving such consent, we do not thereby concede that we are in the category of
persons whose consent is required under Section 7 of the Securities Act or the
rules and regulations



Moore Corporation Limited                                                    -2-

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