MDU Resources Named a Fortune 500 Company

Bismarck, ND

MDU Resources Group, Inc. (NYSE:MDU) has been named to the prestigious Fortune 500 list, which highlights the largest companies in America.

“We are honored to be part of the Fortune 500.  Our corporation’s continuing growth is the result of our successful business strategy and the dedication of our hard-working employees,” said Terry D. Hildestad, president and chief executive officer of MDU Resources. “With our diversified, balanced group of regulated and nonregulated companies providing stable cash flow, we look forward to continuing growth.

“Our success also is a tribute to the strong business climate created by North Dakota’s leaders and the Bismarck community,” he said. “This is an outstanding place to live and work.”

MDU Resources is the only Fortune 500 company headquartered in the four-state region of North Dakota, South Dakota, Montana and Wyoming. The corporation is ranked No. 473 on the 2009 Fortune 500 list, which will appear in Fortune magazine’s May 4 issue.

MDU Resources got its start as a small utility company with operations in western North Dakota and eastern Montana. The company moved to North Dakota from Minnesota in 1968. At the time of the move, it was still primarily a utility business, with revenues of $48 million and about 1,500 employees. Since then, MDU Resources has grown into a diverse company that operates in 44 states, with 2008 revenues of $5 billion and about 10,000 employees. The company operates in three core lines of business: energy, utility resources and construction materials.

The company’s businesses include:

• The natural gas and electric utility business, which has grown to more than 940,000 customers in an eight-state region stretching from Minnesota to the Pacific Coast.  It includes Montana-Dakota Utilities Co., Great Plains Natural Gas Co., Cascade Natural Gas Corporation and Intermountain Gas Company.
• Natural gas and oil production, natural gas pipelines and energy services.  These businesses include WBI Holdings, Inc., Fidelity Exploration & Production Company, Williston Basin Interstate Pipeline Co. and Bitter Creek Pipelines, LLC.
• Knife River Corporation, which is one of the 10 largest aggregate producers in the United States.  The company also produces asphalt, cement, ready-mix concrete and prestress/precast concrete and provides extensive construction services, including aggregate placement, asphalt paving, concrete construction, airport work and marine construction.
• MDU Construction Services Group, Inc., which is one of a handful of U.S. companies that can handle complex inside electrical and mechanical construction.  Its work ranges from casino projects in Las Vegas to renovating Arrowhead football stadium in Kansas City to installing a power distribution system for the Cleveland Heart Clinic.  The company also provides fire suppression services, electric transmission and distribution lines, traffic signalization and industrial turn-around services.

MDU Resources Group, Inc., a Fortune 500 company and a member of the S&P MidCap 400 index, provides value-added natural resource products and related services that are essential to energy and transportation infrastructure, operating in three core lines of business: energy, utility resources and construction materials. MDU Resources includes natural gas and oil production, natural gas pipelines and energy services, electric and natural gas utilities, construction services, and construction materials and contracting. For more information about MDU Resources, see the company's Web site at www.mdu.com.

The information in this release includes forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934. Although the company believes that its expectations are based on reasonable assumptions, actual results may differ materially. For a discussion of factors that could cause actual results to differ, refer to Item 1A – Risk Factors in MDU Resources’ most recent Form 10-K and Form 10-Q.

Contacts:

Financial:
     Vernon A. Raile
     Executive Vice President, Treasurer and Chief Financial Officer
     (701) 530-1003

     Phyllis A. Rittenbach
     Director - Investor Relations
     (701) 530-1057

Media:
     Rick Matteson
     Director of Communications and Public Affairs
     (701) 530-1700

     Laura Lueder
     Corporate Public Relations Manager
     (701) 530-1095