MDU RESOURCES GROUP, INC. Certificate of Amendment of Certificate of Incorporation MDU Resources Group, Inc., a corporation duly organized and existing under the laws of the State of Delaware, hereby certifies as follows: 1. That the Board of Directors of said Corporation, at a meeting duly convened and held on the 12th day of November, 1998, proposed an amendment to the Certificate of Incorporation of the Corporation, as heretofore amended, and at said meeting adopted resolutions setting forth the proposed amendment, declaring its advisability, and directing that the proposed amendment be considered at the next annual meeting of said Corporation by the stockholders entitled to vote in respect thereof, such amendment being set forth in the Corporation's Proxy Statement for the 1999 Annual Stockholders Meeting as follows: RESOLVED, that the Board of Directors of MDU Resources Group, Inc. hereby declares it advisable: (A) That the number of shares of Common Stock which the Company is authorized to issue be increased from 75,000,000 shares of Common Stock with the par value of $3.33, to 150,000,000 shares with the par value of $1.00, effective at the close of business on the date on which the appropriate Certificate of Amendment to the Company's Certificate of Incorporation is filed in the office of the Secretary of State of the State of Delaware; (B) That, in order to effect the foregoing, the Certificate of Incorporation of the Company, as heretofore amended, be further amended by deleting the first paragraph of Article FOURTH, and by inserting in place thereof a new first paragraph of said Article FOURTH to read as follows: FOURTH. The total number of shares of stock which the Corporation shall have authority to issue is One Hundred Fifty-two Million (152,000,000) divided into four classes, namely, Preferred Stock, Preferred Stock A, Preference Stock, and Common Stock. The total number of shares of such Preferred Stock authorized is Five Hundred Thousand (500,000) shares of the par value of One Hundred Dollars ($100) per share (hereinafter called the "Preferred Stock") amounting in the aggregate to Fifty Million Dollars ($50,000,000). The total number of shares of such Preferred Stock A authorized is One Million (1,000,000) shares without par value (hereinafter called the "Preferred Stock A"). The total number of shares of such Preference Stock authorized is Five Hundred Thousand (500,000) shares without par value (hereinafter called the "Preference Stock"). The total number of shares of such Common Stock authorized is One Hundred Fifty Million (150,000,000) of the par value of One and no/100 Dollars ($1.00) per share (hereinafter called the "Common Stock"), amounting in the aggregate to One Hundred Fifty Million Dollars ($150,000,000). FURTHER RESOLVED, that the Board of Directors hereby directs that the proposed amendments be attached as an exhibit to the proxy statement for the Company's next Annual or Special Meeting of Stockholders for consideration by the Stockholders entitled to vote in respect thereof. A copy of the resolutions was attached as Exhibit A to the Corporation's Proxy Statement for the 1999 Annual Stockholders Meeting, and the body of the Proxy Statement contained a discussion of the proposed amendment. 2. That thereafter, on the 27th day of April, 1999, at 11:00 a.m., in accordance with the Bylaws of the Corporation, and upon notice given in accordance with the laws of the State of Delaware and said Bylaws, the Annual Meeting of Stockholders of the Corporation was held, and there were present at such meeting, in person or by proxy, the holders of more than a majority of the shares of Common Stock of the Corporation outstanding and entitled to vote, constituting a quorum of said stockholders. 3. That at said Annual Meeting of Stockholders, the proposal to amend the Certificate of Incorporation to increase the number of authorized shares of Common Stock from 75,000,000 shares to 150,000,000 shares and to reduce the par value of such shares from $3.33 per share to $1.00 per share were presented for consideration, and a vote of the holders of the Common Stock voting in person or by proxy was taken for and against said proposal. That a majority of the outstanding stock of the Corporation entitled to vote and present at the Annual Meeting in person or by proxy voted in favor of the proposal to amend Article FOURTH to the Certificate of Incorporation as indicated in the following table: Shares Shares Shares Shares Voted Voted Out- Repre- For Against standing sented Proposal Proposal Common Stock 53,156,004 46,271,156 41,759,552 4,511,604* *Includes 773,805 abstentions 6. That said amendment to the Certificate of Incorporation of MDU Resources Group, Inc. as hereinbefore set forth have been therefore duly adopted in accordance with the provisions of Section 242 of the General Corporation Laws of the State of Delaware. IN WITNESS WHEREOF, MDU Resources Group, Inc. has caused its corporate seal to be hereunto affixed, and this Certificate to be signed by Martin A. White, its President and Chief Executive Officer, and Lester H. Loble, II, its Secretary, this 28th day of April, 1999. MDU RESOURCES GROUP, INC. ATTEST: /s/ LESTER H. LOBLE, II By: /s/ MARTIN A. WHITE Lester H. Loble, II, Secretary Martin A. White President and Chief Executive Officer