Exhibit 5(b)


                                                June 14, 1996



             MDU Resources Group, Inc.
             400 North Fourth Street
             Bismarck, North Dakota 58501


             Ladies and Gentlemen:

                       With reference to the Registration Statement on
             Form S-8 to be filed on or about the date hereof with the
             Securities and Exchange Commission by MDU Resources Group,
             Inc. (the "Company") under the Securities Act of 1933, as
             amended (the "Act"), and pursuant to which the Company
             intends to register 600,000 shares of its Common Stock, par
             value $3.33 (the "Stock") and the Preference Share Purchase
             Rights attached thereto (the "Rights") for offer and sale
             in connection with the Company's Tax Deferred Compensation
             Savings Plan for Collective Bargaining Unit Employees (the
             "Plan"), we are of the opinion that: 

                       1.   When

                       (a)  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 of the Stock shall
                            have been granted;

                       (b)  the Company's Board of Directors or a duly
                            authorized committee thereof shall have
                            approved the issuance and sale of the Stock
                            by the Company; and

                       (c)  the Stock shall have been duly issued and
                            delivered for the consideration set forth in
                            the aforesaid Registration Statement and in
                            accordance with the actions hereinabove
                            mentioned,

             the Stock will be validly issued, fully paid and non-
             assessable.

                       2.   The Rights, when issued as contemplated by
             the Registration Statement, will be validly issued.

                       We are members of the New York Bar and do not
             hold ourselves out as experts on the laws of any other
             state.  Our opinions expressed above are limited to the law
             of the State of New York, the General Corporation Law of
             the State of Delaware and the Federal laws of the United
             States.  As to all matters of Montana, North Dakota, South
             Dakota and Wyoming law, we have relied upon the opinion to
             you of even date herewith of Lester H. Loble, II, Esq.,
             Bismarck, North Dakota, the Company's General Counsel.

                       We hereby consent to the use of this opinion as
             an exhibit to the Registration Statement and to the use of
             our name therein.

                                           Very truly yours,

                                           /s/ Reid & Priest LLP

                                           REID & PRIEST LLP