Exhibit 5(a)

                             Paul K. Sandness, Esq.
                          General Counsel and Secretary
                            MDU Resources Group, Inc.
                               Schuchart Building
                      918 East Divide Avenue, P.O. Box 5650
                        Bismarck, North Dakota 58506-5650




                                                    August 26, 2004



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

Ladies and Gentlemen:

     I am General Counsel and Secretary of MDU Resources Group, Inc., a Delaware
corporation (the "Company"). This opinion is being rendered in connection with
the Registration Statement on Form S-8 (the "Registration Statement") to be
filed on or about the date hereof with the Securities and Exchange Commission
(the "Commission") by the Company under the Securities Act of 1933, as amended,
(the "Securities Act"), for the registration of 400,000 shares of its common
stock, par value $1.00 per share (the "Stock"), and the preference share
purchase rights attached thereto (the "Rights"), to be issued pursuant to the
MDU Resources Group, Inc. Non-Employee Director Stock Compensation Plan (the
"Plan").

     In connection with this opinion, I have examined originals or copies,
certified or otherwise identified to my satisfaction, of (i) the Registration
Statement, (ii) the Rights Agreement, dated as of November 12, 1998, between the
Company and Wells Fargo Bank, 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, (iii) the Certificate of
Adjustment to Purchase Price and Redemption Price, as amended and restated,
pursuant to the Rights Agreement, (iv) the Restated Certificate of
Incorporation, as amended, and the Bylaws, as amended, of the Company, as in
effect on the date hereof, (v) the Plan, (vi) resolutions of the Board of
Directors of the Company, dated February 12, 2004, authorizing the issuance of
the Stock and (vii) such other instruments, certificates, records and documents,
and such matters of law, as I have considered necessary or appropriate for the
purposes hereof.

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





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

     2. The issuance of the Stock has been duly authorized by the Board of
Directors of the Company.

     3. When the Federal Energy Regulatory Commission, the Montana Public
Service Commission and the Public Service Commission of Wyoming shall have
issued orders authorizing the issuance and sale of the Stock, and provided that
such orders remain in full force and effect and have not been amended, rescinded
or repealed, upon issuance and delivery of the Stock, as set forth in the Plan,
the Stock will be validly issued, fully paid and non-assessable.

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

     Insofar as the opinions expressed herein relate to 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,
or the federal laws of the United States of America, I have relied on the
opinion of even date herewith of LeBoeuf, Lamb, Greene & MacRae, L.L.P., counsel
to the Company, which opinion is to be filed as an exhibit to the Registration
Statement.

     I hereby consent to the use of this opinion as an exhibit to the
Registration Statement and to the use of my name, as counsel, therein. In giving
the foregoing consent, I do not thereby admit that I am in the category of
persons whose consent is required under Section 7 of the Securities Act or the
rules or regulations of the Commission thereunder.

                                             Very truly yours,

                                             /s/ Paul K. Sandness

                                             Paul K. Sandness
                                             General Counsel and
                                               Secretary