Exhibit 5(a)

                               Lester H. Loble, II
                  Vice President, General Counsel and Secretary
                            MDU Resources Group, Inc.
                               Schuchart Building
                             918 East Divide Avenue
                                  P.O. Box 5650
                        Bismarck, North Dakota 58506-5650


                                                                  March 23, 2000


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

Ladies and Gentlemen:

     With reference to 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 by MDU Resources  Group,  Inc.  (the  "Company")  under the
Securities  Act of 1933, as amended,  (the  "Securities  Act"),  and pursuant to
which the Company intends to register  420,000  additional  shares of its Common
Stock,  par value $1.00 (the "Stock") and the Preference  Share Purchase  Rights
attached  thereto (the "Rights"),  for offer and sale in connection with the MDU
Resources Group, Inc. 1998 Option Award Program, it is my 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,

          (c)  the Registration  Statement shall have become effective under the
               Securities Act and



          (d)  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 Rights Agreement,  dated
as of November 12, 1998,  between the Company and Norwest Bank Minnesota,  N.A.,
as Rights Agent, will be validly issued.

     I am a member of the North  Dakota and Montana  Bars and do not hold myself
out as an expert on the laws of any other  jurisdiction.  Except as set forth in
paragraph 1(a) above, my opinions expressed above are limited to the laws of the
States of North Dakota and Montana.  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.

                                             Very truly yours,

                                             /s/ Lester H. Loble, II
                                             Lester H. Loble, II
                                             Vice President, General
                                             Counsel and Secretary