UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K Current Report PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported) April 20, 2004 MDU Resources Group, Inc. (Exact name of registrant as specified in its charter) Delaware 1-3480 41-0423660 (State or other jurisdiction (Commission (I.R.S. Employer of incorporation) File Number) Identification No.) Schuchart Building 918 East Divide Avenue P.O. Box 5650 Bismarck, North Dakota 58506-5650 (Address of principal executive offices) (Zip Code) Registrant's telephone number, including area code (701) 222-7900 Item 12. Results of Operations and Financial Condition. MDU Resources Group, Inc. is furnishing to the Securities and Exchange Commission its first quarter 2004 earnings press release, which is furnished as Exhibit 99. SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. MDU RESOURCES GROUP, INC. Date April 20, 2004 BY /s/ Warren L. Robinson Warren L. Robinson Executive Vice President and Chief Financial Officer EXHIBIT INDEX Exhibit Number Description of Exhibit 99 Press release issued April 20, 2004, regarding earnings for the first quarter.