EXHIBIT 5


October 1, 2003

3M Company
3M Center
St. Paul, MN 55144

Ladies and Gentlemen:

         This will refer to the Post-Effective Amendment No. 1 to the
Registration Statement on Form S-8 (the "Registration Statement") that is being
filed by 3M Company (the "Company") with the Securities and Exchange Commission
(the "Commission") pursuant to the Securities Act of 1933, as amended (the
"Securities Act"), with respect to the registration of additional shares of the
company's common stock (the "Shares") for issuance under the 2002 Management
Stock Ownership Program (the "Plan").

         As Assistant General Counsel of the Company, I am familiar with the
Certificate of Incorporation and the By-Laws of the Company and with its
affairs, including the actions taken by the Company in connection with the
Plan. I also have examined such other documents and instruments and have made
such further investigation as I have deemed necessary or appropriate in
connection with this opinion.

         In my examination, I have assumed the genuineness of all signatures,
the legal capacity of natural persons, and the authenticity of all documents
submitted to me as originals, the conformity to original documents of all
documents submitted to me as certified or photo static copies and the
authenticity of the originals of such copies. I have also assumed that all of
the Shares will be issued for the consideration permitted under the Plan as
currently in effect. Based upon the foregoing, I am of the opinion that:

         1.       The Company is duly incorporated and validly existing as a
                  corporation under the laws of the State of Delaware.

         2.       All necessary corporate proceedings have been taken to
                  authorize the issuance of the Shares being registered under
                  the Registration Statement.

         3.       The Shares covered by this Registration Statement, when issued
                  in accordance with proper corporate authorizations, will be
                  validly issued, fully paid, and nonassessable.

         This opinion is limited to the Federal laws of the United States and
the laws of the State of Minnesota and, with respect to paragraph 1 above, the
General Corporate Laws of the State



of Delaware (including the statutory provisions and all applicable provisions of
the Delaware Constitution and reported judicial decisions interpreting the
General Corporate Laws of the State of Delaware) and I am expressing no opinions
as to the effect of the laws of any other jurisdiction. No one other than those
to whom this letter is addressed is permitted to rely on or distribute this
opinion without my prior written consent.

         I hereby consent to the filing of this opinion as an exhibit to the
Registration Statement, and further consent to the use of my name wherever
appearing in the Registration Statement and any amendment thereto. In giving
this consent, I do not admit that I am within the category of persons whose
consent is required under Section 7 of the Act or the Rules and Regulations of
the Commission issued thereunder.

Very truly yours,

/s/ Gregg M. Larson, Esq.

Gregg M. Larson.
Assistant General Counsel