MDU RESOURCES GROUP, INC.

                              OFFICER'S CERTIFICATE
                                      1-S-1

                 Establishing the Form and Certain Terms of the
                           5.98% Senior Notes due 2033

     The undersigned, Warren L. Robinson, Executive Vice President, Treasurer
and Chief Financial Officer of MDU Resources Group, Inc. (the "Company") (all
capitalized terms used herein which are not defined herein but are defined in
the Indenture referred to below, shall have the meanings specified in the
Indenture), pursuant to a Board Resolution dated December 16, 2003 and Sections
201 and 301 of the Indenture, does hereby certify to The Bank of New York (the
"Trustee"), as Trustee under the Indenture of the Company dated as of December
15, 2003 (as heretofore supplemented, the "Indenture") that:

1.   The Securities of the first series to be issued under the Indenture (the
     "Notes") shall be issued in a series designated "5.98% Senior Notes due
     2033"; the Notes shall be in substantially the form set forth in Exhibit A
     hereto; the Notes shall initially be issued in the aggregate principal
     amount of $30,000,000; however, the aggregate principal amount of Notes
     which may be authenticated and delivered under the Indenture is unlimited;
     and the Notes issued on the original issue date and any additional Notes
     issued thereafter shall be considered one and the same class of securities
     under the Indenture;

2.   The Notes shall mature and the principal shall be due and payable together
     with all accrued and unpaid interest thereon on December 15, 2033, and the
     Company shall not have any right to extend the Maturity of the Notes as
     contemplated in Section 301(d) of the Indenture;

3.   The Notes shall bear interest as provided in the form thereof set forth in
     Exhibit A hereto; the Interest Payment Dates for the Notes shall be June 15
     and December 15 of each year, commencing June 15, 2004;

4.   Each installment of interest on the Notes shall be payable as provided in
     the form thereof set forth as Exhibit A hereto; the Company shall not have
     any right to extend any interest payment periods for the Notes as
     contemplated in Section 301(e) of the Indenture;

5.   The principal of, premium, if any, and each installment of interest on the
     Notes shall be payable and registration of transfers and exchanges in
     respect of the Notes may be effected, at the office or agency of the
     Company in The City of New York and as otherwise provided in the form of
     Note set forth in Exhibit A hereto; and notices and demands to or upon the
     Company in respect of the Notes may be served at the office or agency of
     the Company in The City of New York; the Corporate Trust Office of the
     Trustee will initially be the agency of the Company for such payment,
     registration and registration of transfers and exchanges and service of
     notices and demands, and the Company hereby appoints the Trustee as its
     agent for all such purposes; and the Trustee will initially be the Security
     Registrar and the Paying Agent for the Notes; provided, however, that the
     Company reserves the right to change, by one or more Officer's
     Certificates, any such office or agency and such agent;

6.   The Regular Record Dates for the interest payable on any given Interest
     Payment Date with respect to the Notes shall be May 31 for the June 15
     Interest Payment Date and November 30 for the December 15 Interest Payment
     Date;


<PAGE>


7.   The Notes are subject to redemption as provided in the form thereof set
     forth in Exhibit A hereto;

8.   The Notes are "Benefitted Securities" and shall have the benefit of the
     covenant of the Company contained in Section 707 of the Indenture;

9.   No service charge shall be made for the registration of transfer or
     exchange of the Notes; provided, however, that the Company may require
     payment of a sum sufficient to cover any tax or other governmental charge
     that may be imposed in connection with the exchange or transfer;

10.  The Notes shall be initially issued in global form registered in the name
     of Cede & Co. (as nominee for The Depository Trust Company ("DTC");
     provided, that the Company reserves the right to provide for another
     depository, registered as a clearing agency under the Exchange Act, to act
     as depository for the global Notes (DTC and any such successor depository,
     the "Depository"); beneficial interests in Notes issued in global form may
     not be exchanged in whole or in part for individual certificated Notes in
     definitive form, and no transfer of a global Note in whole or in part may
     be registered in the name of any Person other than the Depository or its
     nominee except that (i) if the Depository (A) has notified the Company that
     it is unwilling or unable to continue as depository for the global Notes or
     (B) has ceased to be a clearing agency registered under the Exchange Act
     and, in either case, a successor depository for such global Notes has not
     been appointed, the Company will execute, and the Trustee, upon receipt of
     a Company Order for the authentication and delivery of definitive Notes,
     will authenticate and deliver Notes in definitive certificated form in an
     aggregate principal amount equal to the principal amount of the global
     Notes representing such Notes in exchange for such global Notes, such
     definitive Notes to be registered in the names provided by the Depository;
     each global Note (i) shall represent and shall be denominated in an amount
     equal to the aggregate principal amount of the outstanding Notes to be
     represented by such global Note (ii) shall be registered in the name of the
     Depository or its nominee, (iii) shall be delivered by the Trustee to the
     Depository, its nominee, any custodian for the Depository or otherwise
     pursuant to the Depository's instruction and (iv) shall bear a legend
     restricting the transfer of such global Note to any person other than the
     Depository or its nominee; none of the Company, the Trustee, any Paying
     Agent or any Authenticating Agent will have any responsibility or liability
     for any aspect of the records relating to, or payments made on account of,
     beneficial ownership interests in a global Note or for maintaining,
     supervising or reviewing any records relating to such beneficial ownership
     interests; the Notes in global form will contain restrictions on transfer,
     substantially as described in the form set forth in Exhibit A hereto;

11.  None of the Trustee, the Security Registrar or the Company shall have any
     liability for any acts or omissions of the Depository, for any transfers of
     beneficial interests in the Notes, for any Depository records of beneficial
     interests, for any transactions between the Depository and beneficial
     owners or in respect of any transfers effected by the Depository or by any
     participant members of the Depository or any beneficial owner of any
     interest in any Notes held through any such participant member of the
     Depository;

12.  If the Company shall make any deposit of money and/or Eligible Obligations
     with respect to any Notes, or any portion of the principal amount thereof,
     as contemplated by Section 801 of the Indenture, the Company shall not
     deliver an Officer's Certificate described in clause (z) in the first
     paragraph of said Section 801 unless the Company shall also deliver to the
     Trustee, together with such Officer's Certificate, either:

     (A) an instrument wherein the Company, notwithstanding the satisfaction and
     discharge of its indebtedness in respect of such Notes, shall assume the
     obligation (which shall be absolute and


                                       -2-

<PAGE>


     unconditional) to irrevocably deposit with the Trustee or Paying Agent such
     additional sums of money, if any, or additional Eligible Obligations
     (meeting the requirements of Section 801), if any, or any combination
     thereof, at such time or times, as shall be necessary, together with the
     money and/or Eligible Obligations theretofore so deposited, to pay when due
     the principal of and premium, if any, and interest due and to become due on
     such Notes or portions thereof, all in accordance with and subject to the
     provisions of said Section 801; provided, however, that such instrument may
     state that the obligation of the Company to make additional deposits as
     aforesaid shall be subject to the delivery to the Company by the Trustee of
     a notice asserting the deficiency accompanied by an opinion of an
     independent public accountant of nationally recognized standing, selected
     by the Trustee, showing the calculation thereof; or

     (B) an Opinion of Counsel to the effect that, as a result of a change in
     law occurring after the date of this certificate, the Holders of such
     Notes, or portions of the principal amount thereof, will not recognize
     income, gain or loss for United States federal income tax purposes as a
     result of the satisfaction and discharge of the Company's indebtedness in
     respect thereof and will be subject to United States federal income tax on
     the same amounts, at the same times and in the same manner as if such
     satisfaction and discharge had not been effected;

13.  The Eligible Obligations with respect to the Notes shall be Government
     Obligations;

14.  The Notes shall have such other terms and provisions as are provided in the
     form set forth in Exhibit A hereto;

15.  No Event of Default under the Indenture has occurred or is occurring;

16.  The undersigned has read all of the covenants and conditions contained in
     the Indenture, and the definitions in the Indenture relating thereto,
     relating to the issuance and authentication and delivery of the Notes and
     in respect of compliance with which this certificate is made;

17.  The statements contained in this certificate are based upon the familiarity
     of the undersigned with the Indenture, the documents accompanying this
     certificate, and upon discussions by the undersigned with officers and
     employees of the Company familiar with the matters set forth herein;

18.  In the opinion of the undersigned, he has made such examination or
     investigation as is necessary to enable him to express an informed opinion
     as to whether or not such covenants and conditions have been complied with;
     and

19.  In the opinion of the undersigned, such conditions and covenants, and all
     conditions precedent provided for in the Indenture (including any covenants
     compliance with which constitutes a condition precedent) relating to the
     authentication and delivery of the Notes requested in the accompanying
     Company Order have been complied with.



                                       -3-

<PAGE>




     IN WITNESS WHEREOF, I have executed this Officer's Certificate this 23rd
day of December, 2003.



                                          /s/ Warren L. Robinson
                                          -----------------------------------
                                          Warren L. Robinson,
                                          Executive Vice President, Treasurer
                                          and Chief Financial Officer







                                      -4-

<PAGE>


                                                                       Exhibit A

                                 [FORM OF NOTE]

         [Unless this certificate is presented by an authorized representative
         of The Depository Trust Company, a New York corporation ("DTC"), to MDU
         Resources Group, Inc., or its agent for registration of transfer,
         exchange, or payment, and any certificate issued is registered in the
         name of Cede & Co. or in such other name as is requested by an
         authorized representative of DTC (and any payment is made to Cede & Co.
         or to such other entity as is requested by an authorized representative
         of DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR
         OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered
         owner hereof, Cede & Co., has an interest herein.]




No._______________                                                     CUSIP No.


                            MDU RESOURCES GROUP, INC.

                           5.98% SENIOR NOTES DUE 2033

     MDU RESOURCES GROUP, INC., a corporation duly organized and existing under
the laws of the State of Delaware (herein referred to as the "Company", which
term includes any successor Person under the Indenture referred to below), for
value received, hereby promises to pay to

or registered assigns, the principal sum of _____________________ ($_________)
Dollars on December 15, 2033, and to pay interest on said principal sum
semi-annually in arrears on June 15 and December 15 of each year commencing June
15, 2004 (each an "Interest Payment Date") at the rate of 5.98% per annum until
the principal hereof is paid or made available for payment. Interest on the
Securities of this series will accrue from and including December 15, 2003, to
and excluding the first Interest Payment Date to which interest has been paid or
duly provided for, and thereafter will accrue from and including the last
Interest Payment Date to which interest has been paid or duly provided for. No
interest will accrue on the Securities of this series with respect to the day on
which the Securities of this series mature. In the event that any Interest
Payment Date is not a Business Day, then payment of interest payable on such
date will be made on the next succeeding day which is a Business Day (and
without any interest or other payment in respect of such delay) with the same
force and effect as if made on the Interest Payment Date. The interest so
payable, and punctually paid or duly provided for, on any Interest Payment Date
will, as provided in such Indenture, be paid to the Person in whose name this
Security (or one or more Predecessor Securities) is registered at the close of
business on May 31 for the June 15 Interest Payment Date and on November 30 for
the December 15 Interest Payment Date (each a "Regular Record Date") immediately
preceding such Interest Payment Date, except that interest payable at Maturity
will be payable to the Person to whom principal shall be paid. Any such interest
not so punctually paid or duly provided for will forthwith cease to be payable
to the Holder on such Regular Record Date and may either be paid to the Person
in whose name this Security (or one or more Predecessor Securities) is
registered at the close of business on a Special Record Date for the payment of
such Defaulted Interest to be fixed by the Trustee, notice whereof shall be
given to Holders of Securities of this series not less than 10 days prior to
such Special Record Date, or be paid at any time in any other lawful manner not
inconsistent with the requirements of any securities exchange on which the
Securities of this series may be listed, and upon such notice as may be required
by such exchange, all as more fully provided in the Indenture referred to
herein.


                                      A-1

<PAGE>


          Payment of the principal of (and premium, if any) and interest at
Maturity on this Security shall be made upon presentation of this Security at
the office or agency of the Company maintained for that purpose in The City of
New York, in the State of New York, in such coin or currency of the United
States of America as at the time of payment is legal tender for payment of
public and private debts; provided, however, that, at the option of the Company,
interest on this Security (other than interest payable at Maturity) may be paid
by check mailed to the address of the person entitled thereto, as such address
shall appear on the Security Register, and provided, further, that if such
person is a securities depositary, such payment may be made by such other means
in lieu of check as shall be agreed upon by the Company, the Trustee and such
person.

          All terms used in this Security which are defined in the Indenture
shall have the meanings assigned to them in the Indenture and in the Officer's
Certificate establishing the terms of the Securities of this series.

          This Security is one of a duly authorized issue of securities of the
Company (herein called the "Securities"), issued and to be issued in one or more
series under an Indenture dated as of December 15, 2003 (herein, together with
any amendments or supplements thereto, called the "Indenture", which term shall
have the meaning assigned to it in such instrument), between the Company and The
Bank of New York, as Trustee (herein called the "Trustee", which term includes
any successor trustee under the Indenture), and reference is hereby made to the
Indenture, for a statement of the property mortgaged, pledged and held in trust,
the nature and extent of the security, the conditions upon which the Lien of the
Indenture may be released and to the Indenture, Board Resolutions and Officer's
Certificate creating the series designated on the face hereof, for a statement
of the respective rights, limitations of rights, duties and immunities
thereunder of the Company, the Trustee and the Holders of the Securities and of
the terms upon which the Securities are, and are to be, authenticated and
delivered. The acceptance of this Security shall be deemed to constitute the
consent and agreement by the Holder thereof to all of the terms and provisions
of the Indenture. This Security is one of the series designated on the face
hereof.

          This Security is subject to redemption at the election of the Company,
in whole or in part, at any time, at a redemption price as calculated by the
Company equal to the greater of:

          100% of the principal amount of the Securities of this series to be
redeemed, and

          a "make-whole" amount, which will be calculated as described below,

plus, in each case, accrued and unpaid interest on such redeemed Securities of
this series to, but excluding, the date of redemption.

          The "make-whole" amount will equal the sum of the present values of
the Remaining Scheduled Payments (as defined below) discounted, on a semiannual
basis (assuming a 360-day year consisting of twelve 30-day months), at a rate
equal to the Treasury Rate (as defined below) plus 12.5 basis points.

          "Remaining Scheduled Payments" means the remaining scheduled payments
of the principal and interest that would be due if the Securities selected for
redemption were not redeemed. However, if the redemption date is not a scheduled
Interest Payment Date, the amount of the next succeeding scheduled interest
payment on those Securities will be reduced by the amount of interest accrued on
those Securities to the redemption date.


                                       A-2

<PAGE>


          "Treasury Rate" means an annual rate equal to the semiannual
equivalent yield to maturity of the Comparable Treasury Issue (as defined
below), assuming a price for the Comparable Treasury Issue (expressed as a
percentage of its principal amount) equal to the Comparable Treasury Price (as
defined below) for the redemption date. The semiannual equivalent yield to
maturity will be computed as of the third Business Day immediately preceding the
redemption date.

          "Comparable Treasury Issue" means the United States Treasury security
selected by UBS Securities LLC or its successor (or, if UBS Securities LLC or
any of its successors ceases to be a primary U.S. Government securities dealer,
another nationally recognized investment banking firm that is a primary U.S.
Government securities dealer appointed by the Company) as having a maturity
comparable to the remaining term of the Securities that would be utilized, at
the time of selection and in accordance with customary financial practice, in
pricing new issues of corporate debt of comparable maturity to the remaining
term of the Securities.

          "Comparable Treasury Price" means the average of three reference
Treasury Dealer Quotations (as defined below) obtained by the Independent
Investment Banker (as defined below) for the redemption date.

          "Independent Investment Banker" means one of the Reference Treasury
Dealers appointed by the Company.

          "Reference Treasury Dealers" means UBS Securities LLC and its
successors, so long as it or any of its successors continues to be a primary
U.S. Government securities dealer, and any two other primary U.S. Government
securities dealers chosen by the Company. If UBS Securities LLC or any of its
successors ceases to be a primary U.S. Government securities dealer, the Company
will appoint in its place another nationally recognized investment banking firm
that is a primary U.S. Government securities dealer.

          "Reference Treasury Dealer Quotation" means the average, as determined
by the Trustee, of the bid and asked prices for the Comparable Treasury Issue
(expressed in each case as a percentage of its principal amount) quoted in
writing to the Trustee by a Reference Treasury Dealer at 3:30 p.m., New York
City time, on the third business day preceding the redemption date.

          The Company shall deliver to the trustee promptly upon its calculation
of any Redemption Price but, in any event, on or before the Redemption Date, an
Officer's Certificate setting forth such Redemption Price. The Trustee may
conclusively rely upon such Officer's Certificate and shall be under no duty to
inquire into, may conclusively presume the correctness of, and shall be fully
protected in relying upon the Company's calculation of such Redemption Price as
set forth therein.

          Notice of redemption (other than at the option of the Holder) shall be
given by mail to Holders of Securities, not less than 30 days prior to the date
fixed for redemption, all as provided in the Indenture. As provided in the
Indenture, notice of redemption at the election of the Company as aforesaid may
state that such redemption shall be conditional upon the receipt by the
applicable Paying Agent or Agents of money sufficient to pay the principal of
and premium, if any, and interest, if any, on this Security on or prior to the
date fixed for such redemption; a notice of redemption so conditioned shall be
of no force or effect if such money is not so received and, in such event, the
Company shall not be required to redeem this Security.

          In the event of redemption of this Security in part only, a new
Security or Securities of this series of like tenor representing the unredeemed
portion hereof shall be issued in the name of the Holder hereof upon the
cancellation hereof.


                                      A-3

<PAGE>


          The Indenture contains provisions for defeasance at any time of the
entire indebtedness of this Security upon compliance with certain conditions set
forth in the Indenture.

          The Indenture contains provisions for release of the Lien thereof upon
compliance with certain conditions set forth therein.

          If an Event of Default with respect to Securities of this series shall
occur and be continuing, the principal of the Securities of this series may be
declared due and payable in the manner and with the effect provided in the
Indenture.

          The Indenture permits, with certain exceptions as therein provided,
the amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders of the Securities of each series to be
affected under the Indenture at any time by the Company and the Trustee with the
consent of the Holders of a majority in principal amount of the Securities at
the time Outstanding of all series to be affected. The Indenture also contains
provisions permitting the Holders of specified percentages in principal amount
of the Securities of each series at the time Outstanding, on behalf of the
Holders of all Securities of such series, to waive compliance by the Company
with certain provisions of the Indenture and certain past defaults under the
Indenture and their consequences. Any such consent or waiver by the Holder of
this Security shall be conclusive and binding upon such Holder and upon all
future Holders of this Security and of any Security issued upon the registration
of transfer hereof or in exchange herefor or in lieu hereof, whether or not
notation of such consent or waiver is made upon this Security.

          As provided in and subject to the provisions of the Indenture, the
Holder of this Security shall not have the right to institute any proceeding
with respect to the Indenture or for the appointment of a receiver or trustee or
for any other remedy thereunder, unless such Holder shall have previously given
the Trustee written notice of a continuing Event of Default with respect to the
Securities of this series, the Holders of a majority in aggregate principal
amount of the Securities of all series at the time Outstanding in respect of
which an Event of Default shall have occurred and be continuing shall have made
written request to the Trustee to institute proceedings in respect of such Event
of Default as Trustee and offered the Trustee reasonable indemnity, and the
Trustee shall not have received from the Holders of a majority in aggregate
principal amount of Securities of all series at the time Outstanding in respect
of which an Event of Default shall have occurred and be continuing a direction
inconsistent with such request, and shall have failed to institute any such
proceeding, for 60 days after receipt of such notice, request and offer of
indemnity. The foregoing shall not apply to any suit instituted by the Holder of
this Security for the enforcement of any payment of principal hereof or any
premium or interest hereon on or after the respective due dates expressed
herein.

          No reference herein to the Indenture and no provision of this Security
or of the Indenture shall alter or impair the obligation of the Company, which
is absolute and unconditional, to pay the principal of and any premium and
interest on this Security at the times, place and rate, and in the coin or
currency, herein prescribed.

          The Securities of this series are issuable only in registered form
without coupons in denominations of $1,000 and integral multiples of $1,000 in
excess thereof. As provided in the Indenture and subject to certain limitations
therein and herein set forth, Securities of this series are exchangeable for a
like aggregate principal amount of Securities of this series and of like tenor
and of authorized denominations, as requested by the Holder surrendering the
same.


                                      A-4

<PAGE>


          No service charge shall be made for any such registration of transfer
or exchange, but the Company may require payment of a sum sufficient to cover
any tax or other governmental charge payable in connection therewith.

          The Company shall not be required to execute and the Security
Registrar shall not be required to register the transfer of or exchange of (a)
Securities of this series during a period of 15 days immediately preceding the
date notice is given identifying the serial numbers of the Securities of this
series called for redemption or (b) any Security so selected for redemption in
whole or in part, except the unredeemed portion of any Security being redeemed
in part. The Company shall not be required to make transfers or exchanges of the
Securities of this series for a period of 15 days next preceding an Interest
Payment Date.

          The Company, the Trustee and any agent of the Company or the Trustee
may treat the Person in whose name this Security is registered as the absolute
owner hereof for all purposes, whether or not this Security be overdue, and
neither the Company, the Trustee nor any such agent shall be affected by notice
to the contrary.

          This Security shall be governed by and construed in accordance with
the laws of the State of New York (including without limitation Section 5-1401
of the New York General Obligations Law or any successor to such statute),
except to the extent that the Trust Indenture Act shall be applicable.

          As provided in the Indenture, no recourse shall be had for the payment
of the principal of or premium, if any, or interest on any Securities, or any
part thereof, or for any claim based thereon or otherwise in respect thereof, or
of the indebtedness represented thereby, or upon any obligation, covenant or
agreement under the Indenture, against, and no personal liability whatsoever
shall attach to, or be incurred by, any incorporator, shareholder, member,
limited partner, officer, manager or director, as such, past, present or future
of the Company or of any predecessor or successor of the Company (either
directly or through the Company or a predecessor or successor of the Company),
whether by virtue of any constitutional provision, statute or rule of law, or by
the enforcement of any assessment or penalty or otherwise; it being expressly
agreed and understood that the Indenture and all the Securities are solely
corporate obligations and that any such personal liability is hereby expressly
waived and released as a condition of, and as part of the consideration for, the
execution of the Indenture and the issuance of the Securities.

          Unless the certificate of authentication hereon has been executed by
the Trustee referred to herein by manual signature, this Security shall not be
entitled to any benefit under the Indenture or be valid or obligatory for any
purpose.


                                      A-5

<PAGE>


          IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed.



                                           MDU RESOURCES GROUP, INC.


                                           By:__________________________________



                     [FORM OF CERTIFICATE OF AUTHENTICATION]

                          CERTIFICATE OF AUTHENTICATION

          This is one of the Securities of the series designated therein
referred to in the within-mentioned Indenture.

Dated:


                                           THE BANK OF NEW YORK, as Trustee


                                           By:__________________________________
                                                    Authorized Signatory



                                      A-6