-------------------------------------------------------------------------------- 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) JUNE 3, 2005 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 CHECK THE APPROPRIATE BOX BELOW IF THE FORM 8-K FILING IS INTENDED TO SIMULTANEOUSLY SATISFY THE FILING OBLIGATION OF THE REGISTRANT UNDER ANY OF THE FOLLOWING PROVISIONS: |_| WRITTEN COMMUNICATIONS PURSUANT TO RULE 425 UNDER THE SECURITIES ACT (17 CFR 230.425) |_| SOLICITING MATERIAL PURSUANT TO RULE 14a-12 UNDER THE EXCHANGE ACT (17 CFR 240.14a-12) |_| PRE-COMMENCEMENT COMMUNICATIONS PURSUANT TO RULE 14d-2(b) UNDER THE EXCHANGE ACT (17 CFR 240.14d-2(b)) |_| PRE-COMMENCEMENT COMMUNICATIONS PURSUANT TO RULE 13e-4(c) UNDER THE EXCHANGE ACT (17 CFR 240.13e-4(c)) -------------------------------------------------------------------------------- ITEM 8.01. OTHER EVENTS. On June 3, 2005, MDU Resources Group, Inc. (the "Company") issued a press release reaffirming the Company's 2005 earnings per share guidance of $1.80 to $2.00 and providing updated information on its coalbed natural gas production program for 2005. A copy of the press release is incorporated by reference herein and is attached as Exhibit 99. ITEM 9.01. FINANCIAL STATEMENTS AND EXHIBITS. (c) Exhibits 99 Press release issued June 3, 2005 2 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 June 3, 2005 BY /s/ Warren L. Robinson --------------------------- ---------------------------- Warren L. Robinson Executive Vice President and Chief Financial Officer 3 EXHIBIT INDEX Exhibit Number Description of Exhibit -------------- ---------------------- 99 Press release issued June 3, 2005 4