CERTIFICATION


I, Martin A. White, certify that:

  1.  I have reviewed this quarterly report on Form 10-Q of MDU
      Resources Group, Inc.;

  2.  Based on my knowledge, this report does not contain any untrue
      statement of a material fact or omit to state a material fact
      necessary to make the statements made, in light of the
      circumstances under which such statements were made, not
      misleading with respect to the period covered by this report;

  3.  Based on my knowledge, the financial statements, and other
      financial information included in this report, fairly present in
      all material respects the financial condition, results of
      operations and cash flows of the registrant as of, and for, the
      periods presented in this report;

  4.  The registrant's other certifying officer and I are responsible
      for establishing and maintaining disclosure controls and
      procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-
      15(e)) and internal control over financial reporting (as defined
      in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the
      registrant and have:

      (a) Designed such disclosure controls and procedures, or
          caused such disclosure controls and procedures to be designed
          under our supervision, to ensure that material information
          relating to the registrant, including its consolidated
          subsidiaries, is made known to us by others within those
          entities, particularly during the period in which this report
          is being prepared;

      (b) Designed such internal control over financial reporting,
          or caused such internal control over financial reporting to
          be designed under our supervision, to provide reasonable
          assurance regarding the reliability of financial reporting
          and the preparation of financial statements for external
          purposes in accordance with generally accepted accounting
          principles;

      (c) Evaluated the effectiveness of the registrant's
          disclosure controls and procedures and presented in this
          report our conclusions about the effectiveness of the
          disclosure controls and procedures, as of the end of the
          period covered by this report based on such evaluation; and

      (d) Disclosed in this report any change in the registrant's
          internal control over financial reporting that occurred
          during the registrant's most recent fiscal quarter (the
          registrant's fourth fiscal quarter in the case of an annual
          report) that has materially affected, or is reasonably likely
          to materially affect, the registrant's internal control over
          financial reporting; and

  5.  The registrant's other certifying officer and I have disclosed,
      based on our most recent evaluation of internal control over
      financial reporting, to the registrant's auditors and the audit
      committee of the registrant's board of directors (or persons
      performing the equivalent functions):

      (a) All significant deficiencies and material weaknesses in
          the design or operation of internal control over financial
          reporting which are reasonably likely to adversely affect the
          registrant's ability to record, process, summarize and report
          financial information; and

      (b) Any fraud, whether or not material, that involves
          management or other employees who have a significant role in
          the registrant's internal control over financial reporting.


Date:  May 4, 2005


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