CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350,
             AS ADOPTED PURSUANT TO SECTION 906
              OF THE SARBANES-OXLEY ACT OF 2002

     Each of the undersigned, Martin A. White, the Chairman
of the Board, President and Chief Executive Officer, and
Warren L. Robinson, the Executive Vice President and Chief
Financial Officer of MDU Resources Group, Inc. (the
"Company"), DOES HEREBY CERTIFY that:

     1.  The Company's Annual Report on Form 10-K for the
year ended December 31, 2003 (the "Report"), fully complies
with the requirements of Section 13(a) of the Securities
Exchange Act of 1934; and

     2.  Information contained in the Report fairly
presents, in all material respects, the financial condition
and results of operation of the Company.

     IN WITNESS WHEREOF, each of the undersigned has
executed this statement this 27th day of February, 2004.


                              /s/ Martin A. White
                              Martin A. White
                              Chairman of the Board, President and
                              Chief Executive Officer



                              /s/ Warren L. Robinson
                              Warren L. Robinson
                              Executive Vice President and
                              Chief Financial Officer


A signed original of this written statement required by
Section 906 has been provided to MDU Resources Group, Inc.
and will be retained by MDU Resources Group, Inc. and
furnished to the Securities and Exchange Commission or its
staff upon request.