EXHIBIT 5


December 10, 2002

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

RE:      Registration Statement on Form S-8 - 2002 Management Stock Ownership
         Program

Ladies and Gentlemen:

         This will refer 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
proposed issuance of up to 15,000,000 shares of common stock, $0.01 par value,
of the Company (the "Common Stock"), pursuant to the 2002 Management Stock
Ownership Program of the Company (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, the authenticity of all documents
submitted to me as originals, the conformity to original documents of all
documents submitted to me as certified or photostatic copies and the
authenticity of the originals of such copies.

         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 Common Stock being registered
                  under the Registration Statement.




         3.       When issued and sold in the manner referred to in the Plan,
                  the Common Stock will be duly authorized, legally and validly
                  issued, fully paid and nonassessable.

         This opinion is limited to the Federal laws of the United States and
the Delaware General Corporation Law (including the statutory provisions and all
applicable provisions of the Delaware Constitution and reported judicial
decisions interpreting the Delaware General Corporation Law) 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 are 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 to the use of my name wherever appearing in the
Registration Statement and any amendments 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