John G. Harp 2008 Additional Incentive Opportunity

Mr. Harp has an additional incentive opportunity for 2008 based on MDU
Construction Services Group, Inc.’s (CSG) financial results.  If CSG’s actual
2008 return on invested capital (ROIC) is 200 basis points or more above its
2008 weighted average cost of capital, Mr. Harp will be paid $200,000.  If the
goal is not met, Mr. Harp will not be eligible to receive any amount under this
incentive opportunity.

The Compensation Committee of the Board of Directors of MDU Resources Group,
Inc. shall determine whether or not the goal has been met and recommend to the
Board of Directors of MDU Resources Group, Inc. (the "Board") whether or not to
approve payment of the additional incentive opportunity to Mr. Harp.  If the
Board approves payment of the additional incentive opportunity, payment will be
made in cash between January 1, 2009 and March 10, 2009.