<DOCUMENT>
<TYPE>EX-5
<SEQUENCE>5
<FILENAME>ex5b.txt
<DESCRIPTION>EXHIBIT 5(B) OPINION OF LLG&M
<TEXT>
                                                              Exhibit 5(b) and 8


                         LeBoeuf, Lamb, Greene & MacRae
                                     L.L.P.
                             New York, NY 10019-5389
                                 (212) 424-8000
                            Facsimile: (212) 424-8500






                                     March 7, 2003


MDU Resources Group, Inc.
Schuchart Building
918 East Divide Avenue
P.O. Box 5650
Bismarck, North Dakota  58506-5650

Ladies and Gentlemen:

     We are acting as counsel for MDU Resources Group, Inc., a Delaware
corporation (the "Company"), in connection with the preparation and filing with
the Securities and Exchange Commission (the "Commission") under the Securities
Act of 1933, as amended, (the "Securities Act") of Post-Effective Amendment No.
1 (the "Post-Effective Amendment") to the Company's registration statement on
Form S-3 (File No. 333-06127) (the "Registration Statement"), relating to the
issuance and sale by the Company of additional shares of its Common Stock, par
value $1.00 per share (the "Stock"), and the Preference Share Purchase Rights
attached thereto (the "Rights") pursuant to the Company's Dividend Reinvestment
and Direct Stock Purchase Plan (the "Plan").

     In connection with this opinion, we have examined originals or copies,
certified or otherwise identified to our satisfaction, of (i) the Registration
Statement, (ii) the Post-Effective Amendment, (iii) the Rights Agreement, dated
as of November 12, 1998, between the Company and Wells Fargo Bank Minnesota,
N.A. (formerly known as Norwest Bank Minnesota, N.A.), as Rights Agent, together
with the exhibits thereto (the "Rights Agreement"), pursuant to which the Rights
were created, (iv) the Restated Certificate of Incorporation, as amended, and
the Bylaws, as amended, of the Company, as in effect on the date hereof, (v)
resolutions of the Board of Directors of the Company, dated February 13, 2003,
relating to the amendment and restatement of the Plan and the filing of the
Post-Effective Amendment, (vi) the orders of the Federal Energy Regulatory
Commission dated July 25, 1996, the Montana Public Service Commission dated July
8, 1996 and the Public Service Commission of Wyoming dated July 26, 1996, which
permit the issuance of up to 3,273,273 shares of common stock in connection with
the Plan and (vii) such other instruments, certificates, records and documents,
and such matters of law, as we have considered necessary or appropriate for the
purposes hereof. In such examination, we have



<PAGE>

MDU Resources Group, Inc.
March 7, 2003
Page 2


assumed the genuineness of all signatures, the authenticity of all documents
submitted to us as originals, the conformity to the original documents of all
documents submitted to us as copies and the authenticity of the originals of
such latter documents. As to any facts material to our opinion, we have, when
relevant facts were not independently established, relied upon the aforesaid
Registration Statement, Post-Effective Amendment, Rights Agreement, resolutions,
orders, instruments, certificates, records and documents. We have also assumed
the regularity of all corporate procedures.

     Based upon the foregoing, and subject to the limitations and qualifications
contained in this opinion, we are of the opinion that:

1.   The Stock will be validly issued, fully paid and non-assessable when the
     Stock shall have been issued, sold and delivered for the consideration
     contemplated in the Plan.

2.   The issuance of the Rights has been validly authorized by all necessary
     corporate action on the part of the Company and, when issued in accordance
     with the Rights Agreement, will be legally issued and binding obligations
     of the Company.

3.   The Stock to be purchased in the open market is validly issued, fully paid
     and non-assessable, and the Rights attached thereto are legally issued and
     binding obligations of the Company.

4.   The statements made in the Post-Effective Amendment under the heading
     "Federal Income Tax Consequences" constitute an accurate description of
     certain Federal income tax consequences to participants in the Plan.

     In rendering the opinion set forth in paragraph "1" above, we have
necessarily assumed that the appropriate authorizations by the Federal Energy
Regulatory Commission, the Montana Public Service Commission and the Public
Service Commission of Wyoming with respect to the issuance and sale by the
Company of shares of Stock beyond the number approved in the 1996 authorizations
referred to above will be obtained and that the 1996 authorizations and such
additional authorizations remain or will be, as the case may be, in full force
and effect.

     We express no opinion with respect to any laws other than the General
Corporation Law of the State of Delaware, the applicable provisions of the
Delaware Constitution and the reported judicial decisions interpreting the
Delaware laws, and the federal laws of the United States. Insofar as this
opinion involves matters of the laws of the States of Minnesota, Montana, North
Dakota, South Dakota and Wyoming, we have relied upon the opinion of even date
herewith addressed to you by Lester H. Loble, II, Esq., Executive Vice
President, General Counsel and Secretary of the Company, which opinion is to be
filed as exhibit to the Post-Effective Amendment.

         We hereby consent to the use of this opinion as an exhibit to the
Post-Effective



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MDU Resources Group, Inc.
March 7, 2003
Page 3


Amendment and to the references to us under the heading "Legal Opinions" in the
Post-Effective Amendment and in the Prospectus constituting a part thereof. In
giving such consent, we do not thereby concede that we are within the category
of persons whose consent is required under Section 7 of the Securities Act or
the rules and regulations of the Commission thereunder.

                                     Very truly yours,

                                     /s/ LeBoeuf, Lamb, Greene & MacRae, L.L.P.

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</DOCUMENT>
