<PAGE>   1


   As filed with the Securities and Exchange Commission on September 17, 2001

================================================================================

                              Registration No. 333-

                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                                    --------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933


                        FIRST INTERSTATE BANCSYSTEM, INC.
               --------------------------------------------------
               (Exact name of issuer as specified in its charter)


           MONTANA                                             81-0331430
-------------------------------                          ----------------------
(State or other Jurisdiction of                            (I.R.S. Employer
incorporation or organization)                           Identification Number)


                 400 North 31st Street, Billings, Montana 59116
              -----------------------------------------------------
              (Address of Principal Executive Offices and Zip Code)

            FIRST INTERSTATE BANCSYSTEM, INC. 2001 STOCK OPTION PLAN
            --------------------------------------------------------
                              (Full title of plan)

                                Terrill R. Moore
                Senior Vice President and Chief Financial Officer
                        FIRST INTERSTATE BANCSYSTEM, INC.
                              401 North 31st Street
                             Billings, Montana 59116
                -------------------------------------------------
                     (Name and address of agent for service)

                                 (406) 255-5300
          -------------------------------------------------------------
          (Telephone number, including area code, of agent for service)

                                  With Copy to:
                               Holland & Hart LLP
                          Attn: Dennis M. Jackson, Esq.
                       555 Seventeenth Street, Suite 3200
                             Denver, Colorado 80202
                                 (303) 295-8115


                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------------------------------
                                                        Proposed                Proposed
Title of Securities to        Amount to be          maximum offering        maximum aggregate          Amount of
be registered                registered (1)        price per share(2)        offering price        registration fee
----------------------------------------------------------------------------------------------------------------------
<S>                          <C>                   <C>                      <C>                    <C>
Common Stock
(no par value)                   750,000                 $40.00                $30,000,000              $7,500
----------------------------------------------------------------------------------------------------------------------
</TABLE>

(1)      Pursuant to Rule 416(a) under the Securities Act of 1933, as amended
         (the "Securities Act"), this Registration Statement shall also cover
         any additional shares of the Registrant's Common Stock, no par value,
         which are issued or become issuable under the First Interstate
         BancSystem, Inc. 2001 Stock Option Plan.

(2)      Calculated in accordance with Rule 457(h) under the Securities Act,
         based upon the latest appraised value of $40.00 per share for 750,000
         shares reserved for issuance under the First Interstate BancSystem,
         Inc. 2001 Stock Option Plan.


================================================================================

<PAGE>   2


                                     PART I

              INFORMATION REQUIRED IN THE SECTION (10(A) PROSPECTUS


         The documents containing the information required by Part I of Form S-8
will be sent or given to participants in the First Interstate BancSystem, Inc.
Stock Option Plan (the "Plan") as specified by Rule 428(b)(1) under the
Securities Act. In reliance on Rule 428, such documents (i) are not being filed
with the Securities and Exchange Commission (the "Commission") either as part of
this registration statement or as prospectuses or prospectus supplements
pursuant to Rule 424, and (ii) along with the documents incorporated by
reference into this registration statement pursuant to Item 3 of Part II hereof,
constitute a prospectus (the "Prospectus") that meets the requirements of
Section 10(a) of the Securities Act.

                                     PART II

Item 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

         The following documents filed by First Interstate BancSystem, Inc. (the
"Registrant") with the Securities and Exchange Commission are hereby
incorporated by reference in this Registration Statement:

         (a) The Registrant's latest Annual Report, filed pursuant to Section
15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"),
on Form 10-K, for the fiscal year ended December 31, 2000.

         (b) The Registrant's Quarterly Report on Form 10-Q for the three months
ended March 31, 2001.

         (c) The Registrant's Quarterly Report on Form 10-Q for the three and
six months ended June 30, 2001.

         (d) The Registrant's amended Annual Reports, filed pursuant to Section
15(d) of the Securities Exchange Act of 1934 (the "Exchange Act"), on Form
10-K/A for the fiscal years ended December 31, 1997, 1998 and 1999.

         (e) The Registrant's amended Quarterly Reports, for the three-month
periods ended on March 31, June 30 and September 30 of each of 1997, 1998 and
1999, on Form 10-Q/A.

         (f) The Registrant's Current Reports on Form 8-K filed on June 1, 2001
and July 20, 2001 and Registrant's amended Current Report on Form 8-K/A filed on
June 8, 2001.

         (g) All documents filed subsequent hereto by the Registrant, pursuant
to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing
of a post-effective amendment which indicates that all securities offered have
been sold or which deregisters all securities then remaining unsold.

Item 4.  DESCRIPTION OF SECURITIES.

         The authorized capital stock of the Registrant consists of 20,000,000
shares of common stock without par value (the "Common Stock"), of which
7,830,303 shares were outstanding as of July 31, 2001, and 100,000 shares of
preferred stock without par value, none of which were outstanding as of July 31,
2001.



                                       2

<PAGE>   3


COMMON STOCK

         Each share of the Common Stock is entitled to one vote in the election
of directors and in all other matters submitted to a vote of shareholders.
Accordingly, holders of a majority of the shares of Common Stock entitled to
vote in any election of directors may elect all of the directors standing for
election if they choose to do so, subject to the rights of the holders of the
preferred stock. Voting for directors is noncumulative.

         Subject to the preferential rights of any preferred stock that may at
the time be outstanding, each share of Common Stock has an equal and ratable
right to receive dividends when, if and as declared by the Board of Directors
out of assets legally available therefor. In the event of a liquidation,
dissolution or winding up of the Company, the holders of Common Stock will be
entitled to share equally and ratably in the assets available for distribution
after payments to creditors and to the holders of any preferred stock that may
at the time be outstanding. Holders of Common Stock have no conversion rights or
preemptive or other rights to subscribe for any additional shares of Common
Stock or for other securities. All outstanding Common Stock is fully paid and
non-assessable.

         The Common Stock of the Company is not actively traded, and there is no
established trading market for the stock. There is only one class of Common
Stock, with approximately 92% of the shares subject to contractual transfer
restrictions set forth in one of four shareholder agreements and approximately
8% held by 13 shareholders without such restrictions. The Company has the right
of first refusal to purchase the restricted stock at fair market value per share
("Fair Market Value") determined as follows: (i) if the Common Stock is listed
on any established stock exchange or a national market system, fair market value
shall be the closing sales price for the Common Stock as quoted on such exchange
or system for the last market trading day prior to the date of determination;
(ii) if the Common Stock is regularly quoted by a recognized securities dealer
but selling prices are not reported, fair market value shall be the mean between
the high bid and the low asked prices for the Common Stock on the last market
trading day prior to the date of determination; or (iii) in the absence of an
established market for the Common Stock, fair market value shall be determined
in good faith by the Board which may, in its sole discretion, utilize an
independent third party to assist with the determination of the fair market
value, which may take the form of a periodic appraisal of the fair market value
of a share of Common Stock valued as a minority interest. The appraised minority
value of the Common Stock represents the estimated fair market valuation of a
minority block of such stock, taking into account adjustments for the lack of
marketability of the stock and other factors. This value does not represent an
actual trading price between a willing buyer and seller of the Common Stock in
an informed, arm's-length transaction. As such, the appraised minority value is
only an estimate as of a specific date, and there can be no assurance that such
appraisal is an indication of the actual value holders of the Common Stock may
realize with respect to shares held by them. Moreover, the estimated fair market
value of the Common Stock may be materially different at any date other than the
valuation dates indicated above.

         All stock not subject to such restrictions may be sold at a price per
share that is acceptable to the shareholder.

         Resale of the Common Stock may be restricted pursuant to the Securities
Act and applicable state securities laws. In addition, most shares of the Common
Stock are subject to one of four shareholders' agreements. Members of the Scott
family, as majority shareholders of the Company, are subject to a shareholder's
agreement (the "Scott Agreement"). The Scott family, under the Scott Agreement,
has agreed to limit the transfer of shares owned by members of the Scott family
to family members or charities, or with the Company's approval, to the Company's
officers, directors (including advisory directors), employees, or to the
Company's Savings and Profit Sharing Plan for Employees of First Interstate
BancSystem, Inc. (the "Savings Plan").

         Shareholders of the Company who are not Scott family members, with the
exception of 13 shareholders who own an aggregate of approximately 600,000
shares of unrestricted stock, are subject to one of three shareholder's
agreements. Shares of Common Stock hereby offered to Participants who are not
Scott family members are subject to execution of the shareholder's agreement
dated August 24, 2001 (the "2001 Shareholder's Agreement"). Upon execution of
the 2001 Shareholder's Agreement, all previous shareholder's agreements,
including the Shareholder's Agreement described below, shall be



                                       3



<PAGE>   4



superceded. The 2001 Shareholder's Agreement grants the Company the right to
acquire some or all of the Common Stock at any time at the Fair Market Value of
the Common Stock. Common Stock subject to the 2001 Shareholder's Agreement may
not be sold or transferred by the shareholder without triggering the Company's
first right of refusal to acquire the stock.

         Charities that received gifts of Common Stock from existing
shareholders prior to August 1, 2001 are subject to a restrictive shareholder's
agreement, which gives the Company the right to repurchase the stock in any of
the following events: 1) the charity's intention to sell the stock, 2) transfer
of the stock by operation of law, and 3) at any other time as determined by the
Company. Charities receiving gifts of stock subsequent to August 1, 2001 will be
subject to the 2001 Shareholder's Agreement.

         Prior to execution of the 2001 Shareholder's Agreement, shareholders of
the Company who are not Scott family members or charities, with the exception of
13 shareholders owning unrestricted stock, are subject to a different form of
shareholder's agreement (the "Shareholder's Agreement"). The Shareholder's
Agreement grants the Company the option to purchase Common Stock in any of the
following events: 1) the shareholder's intention to sell the stock, 2) the
shareholder's death, 3) transfer of the stock by operation of law, 4)
termination of the shareholder's status as a director, officer or employee of
the Company, and 5) total disability of the shareholder. Stock subject to the
Shareholder's Agreement may not be sold or transferred by the shareholder
without triggering the Company's option to acquire the stock in accordance with
the terms of the Shareholder's Agreement. In addition, the Shareholder's
Agreement allows the Company to repurchase any of the Common Stock acquired by
the shareholder after January 1, 1994 if the Company determines that the number
of shares owned by the shareholder is excessive in view of a number of factors,
including, but not limited, to (a) the relative contribution of the shareholder
to the economic performance of the Company, (b) the effort being put forth by
the shareholder, and (c) the level of responsibility of the shareholder.

         The Trust Department of First Interstate Bank in Montana ("FIB
Montana"), a subsidiary of the Company (the "Savings Plan Trustee"), is the
Trustee of the Savings Plan. The Savings Plan Trustee owns shares of Common
Stock which are allocated to the accounts of participants in the Savings Plan
and votes the shares based on the instructions of each participant therein. In
the event a participant does not provide the Savings Plan Trustee with
instructions, the Savings Plan Trustee will vote the shares allocated to such
Participant in accordance with voting instructions received from a majority of
the participants in the Savings Plan. The Savings Plan Trustee receives
reasonable compensation for its service as such.

         Purchases of the Common Stock made through the Savings Plan are not
restricted by any shareholder's agreement, due to requirements of ERISA and the
Code. However, since the Savings Plan does not allow distributions "in kind,"
any distributions from an employee's account in the Savings Plan will allow, and
may require, the Savings Plan Trustee to sell the Common Stock. While the
Company has no obligation to repurchase the Common Stock, it is possible that
the Company will repurchase the Common Stock sold out of the Savings Plan. Any
such repurchases would be upon terms set by the Savings Plan Trustee and
accepted by the Company.

DIVIDENDS

         It is the policy of the Company to pay a dividend to all holders of the
Common Stock on a quarterly basis. Dividends are declared and paid in the month
following the calendar quarter and the amount has historically been determined
based upon a percentage of net income for the calendar quarter immediately
preceding the dividend payment date. Effective with the dividend for the fourth
quarter of 1995 paid in January 1996, the dividend has been 30% of quarterly net
income without taking into effect compensation expense related to stock options.
The Board of Directors of the Company has no current intention to change its
dividend policy, but no assurance can be given that the Board may not, in the
future, change or eliminate the payment of dividends.



                                       4

<PAGE>   5


DIVIDEND RESTRICTIONS

         The holders of Common Stock will be entitled to dividends when, as and
if declared by the Company's Board of Directors out of funds legally available
therefor. As a holding company, the Company is a corporation separate and apart
from its bank subsidiaries, FIB Montana and First Interstate Bank in Wyoming
(together, the "Banks"). The Company's ability to pay dividends to its
stockholders is dependent upon the cash dividend payments received by the
Company from the Banks. Dividend payments from the Banks are subject to federal
and state banking limitations, generally based on current and retained earnings,
imposed by the various federal and state regulatory agencies with authority over
the respective Banks. Payment of dividends by the Banks is also subject to each
respective Bank's profitability, financial condition, capital expenditures and
cash flow requirements. Payment of dividends may also be restricted by
applicable banking regulations if such dividends would impair the capital of the
respective Banks or constitute an "unsafe or unsound" practice. In addition,
there are restrictions and financial covenants in the Company's debt instruments
which may prohibit the payment of dividends from the Banks to the Company and
from the Company to its stockholders in certain circumstances.

PREFERRED STOCK

         The authorized capital stock of the Company includes 100,000 shares of
preferred stock. The Company's Board of Directors is authorized, without
approval of the holders of the Common Stock, to provide for the issuance of
preferred stock from time to time in one or more series in such number and with
such designations, preferences, powers and other special rights as may be stated
in the resolution or resolutions providing for such preferred stock. The
Company's Board of Directors may cause the Company to issue preferred stock with
voting, conversion and other rights that could adversely affect the holders of
the Common Stock by making it more difficult to effect a change in control of
the Company.

         In the event of any dissolution, liquidation or winding up of the
affairs of the Company, before any distribution or payment may be made to the
holders of the Common Stock, the holders of preferred stock would be entitled to
be paid in full with the respective amounts fixed by the Company's Board of
Directors in the resolution or resolutions authorizing the issuance of such
series, together with a sum equal to the accrued and unpaid dividends thereon to
the date fixed for such distribution or payment. After payment in full of the
amount which the holders of preferred stock are entitled to receive, the
remaining assets of the Company would be distributed ratably to the holders of
the Common Stock. If the assets available are not sufficient to pay in full the
amount so payable to the holders of all outstanding preferred stock, the holders
of all series of such shares would share ratably in any distribution of assets
in proportion to the full amounts to which they would otherwise be respectively
entitled. The consolidation or merger of the Company into or with any other
corporation or corporations would not be deemed a liquidation, dissolution, or
winding up of the affairs of the Company.

Item 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL

         Not Applicable

Item 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Officers and directors of the Registrant are entitled to
indemnification under the Montana Business Corporation Act and pursuant to a
Resolution of the Board of Directors of the Registrant dated January 12, 1987. A
summary of the indemnification provision in such resolution follows:

         Pursuant to a resolution of the Board of Directors dated January 12,
1987, and under the authority of Section 35-1-414 of the Montana Business
Corporation Act, the Registrant shall indemnify each director and officer of the
Registrant (including former officers and directors) and each agent of the
Registrant serving as a director or officer of a Bank, serving at the specific
direction or request of the Registrant (but only to the extent that such
director, officer or agent is not indemnified by the Bank or by insurance
provided by the Registrant) against judgments, penalties, fines, settlements and
reasonable expenses actually and reasonably paid by such director, officer or
agent by reason of the fact that he or she is or was a director or officer of
the Registrant or such Bank, to the extent provided by and subject to the
limitations of the Montana Business Corporation Act.



                                       5


<PAGE>   6



         Officers and directors of the Registrant are also entitled to
indemnification under the Registrant's Bylaws, a copy of which is included as an
exhibit hereto.

Item 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         Not Applicable.

Item 8.  EXHIBITS

<TABLE>
<CAPTION>
     Regulation S-K
         Exhibit                                                   Document
     --------------                                                --------
<S>                        <C>
       4.1(1)              Restated Articles of Incorporation of the Registrant dated February 27, 1986

       4.2(2)              Articles of Amendment to Restated Articles of Incorporation of the Registrant dated
                           September 19, 1996

       4.3(2)              Articles of Amendment to Restated Articles of Incorporation of the Registrant dated
                           September 19, 1996

       4.4(3)              Articles of Amendment to Restated Articles of Incorporation of the Registrant dated
                           October 7, 1997

       4.5(3)              Bylaws of the Registrant

       4.5(4)              Amendment to Bylaws of the Registrant dated March 18, 1999

       4.6                 Amendment to Bylaws of the Registrant dated May 18, 2001

       4.7(5)              Specimen of common stock certificate of First Interstate BancSystem, Inc.

       4.8(1)              Shareholder's Agreement for non-Scott family members

       4.9(7)              Shareholder's Agreement for non-Scott family members dated August 24, 2001

       4.8                 2001 Stock Option Plan of the Registrant

       4.9(6)              First Interstate Stockholders' Agreements with Scott family members

       5                   Opinion of Holland & Hart LLP, as to the legality of securities being registered.

       23.1                Consent of KPMG LLC, Independent Certified Public Accountants

       23.2                Consent of Holland & Hart LLP (contained in Exhibit 5)

       24                  Power of Attorney (included on page 10 of this Registration Statement)
</TABLE>

                     * * * * * * * * * * * * * * * * * * * *

(1)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-1, No. 333-84540.

(2)      Incorporated by reference to the Registrant's Form 8-K dated October 1,
         1996.



                                       6


<PAGE>   7


(3)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-1, No. 333-37847.

(4)      Incorporated by reference to the Registrant's Form 10-K for the fiscal
         year ended December 31, 1999, No. 033-64304.

(5)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-1, No. 333-3250.

(6)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-8, No. 333-76825.

(7)      Incorporated by reference to the Registrant's Post-Effective Amendment
         No. 1 to Registration Statement on Form S-8, No. 333-76825

Item 9.  UNDERTAKINGS

         (a) The undersigned Registrant hereby undertakes:

                  (1)      To file, during any period in which offers or sales
                           are being made, a post-effective amendment to this
                           registration statement:

                           (i)      To include any prospectus required by
                                    Section 10(a)(3) of the Securities Act;

                           (ii)     To reflect in the prospectus any facts or
                                    events arising after the effective date of
                                    the registration statement (or the most
                                    recent post-effective amendment thereof)
                                    which, individually or in the aggregate,
                                    represent a fundamental change in the
                                    information set forth in the registration
                                    statement;

                           (iii)    To include any material information with
                                    respect to the plan of distribution not
                                    previously disclosed in the registration
                                    statement or any material change to such
                                    information in the registration statement;

                           provided, however, that paragraphs (a)(1)(i) and
                           (a(1)(ii) do not apply if the registration statement
                           is on Form S-3 or Form S-8, and the information
                           required to be included in a post-effective amendment
                           by those paragraphs is contained in periodic reports
                           filed with or furnished to the Commission by the
                           Registrant pursuant to Section 13 or Section 15(d) of
                           the Exchange Act that are incorporated by reference
                           in the registration statement.

                  (2)      That, for the purpose of determining any liability
                           under the Securities Act, each such post-effective
                           amendment shall be deemed to be a new registration
                           statement relating to the securities offered therein,
                           and the offering of such securities at that time
                           shall be deemed to be the initial bona fide offering
                           thereof.

                  (3)      To remove from the registration by means of a
                           post-effective amendment any of the securities being
                           registered which remain unsold at the termination of
                           the offering.

         (b)      The undersigned Registrant hereby undertakes that, for
                  purposes of determining any liability under the Securities
                  Act, each filing of the Registrant's annual report pursuant to
                  Section 13(a) or Section 15(d) of the Exchange Act that is
                  incorporated by reference in this registration statement shall
                  be deemed to be a new registration statement relating to the
                  securities offered therein, and the offering of such
                  securities at that time shall be deemed to be the initial bona
                  fide offering thereof.


                                       7


<PAGE>   8



         (c)      Insofar as indemnification for liabilities arising under the
                  Securities Act may be permitted to directors, officers and
                  controlling persons of the Registrant pursuant to the
                  foregoing provisions, or otherwise, the Registrant has been
                  advised that in the opinion of the Securities and Exchange
                  Commission such indemnification is against public policy as
                  expressed in the Securities Act and is, therefore,
                  unenforceable. In the event that a claim for indemnification
                  against such liabilities (other than the payment by the
                  Registrant of expenses incurred or paid by a director, officer
                  or controlling person of the Registrant in the successful
                  defense of any action, suit or proceeding) is asserted by such
                  director, officer or controlling person in connection with the
                  securities being registered, the Registrant will, unless in
                  the opinion of its counsel the matter has been settled by
                  controlling precedent, submit to a court of appropriate
                  jurisdiction the question whether such indemnification by it
                  is against public policy as expressed in the Securities Act
                  and will be governed by the final adjudication of such issue.


                                   SIGNATURES

1.       REGISTRANT

         Pursuant to the requirements of the Securities Act, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Billings, State of Montana, on August 31, 2001.

                                       First Interstate BancSystem, Inc.

                                       By: /s/ Thomas W. Scott
                                           -------------------------------------
                                           Thomas W. Scott
                                           President and Chief Executive Officer





                                       8

<PAGE>   9



                                POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature to
this Registration Statement appears below hereby constitutes and appoints Thomas
W. Scott and Terrill R. Moore, and each of them, as his true and lawful
attorney-in-fact and agent, with full power of substitution, to sign on his
behalf individually and in the capacity stated below, and to perform any acts
necessary to be done in order to file all amendments and post-effective
amendments to this Registration Statement, and any and all instruments or
documents filed as part of or in connection with this Registration Statement or
the amendments thereto and each of the undersigned does hereby ratify and
confirm all that such attorney-in-fact and agent, or his substitutes, shall do
or cause to be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, the
Registration Statement has been signed below by the following persons in the
capacities indicated on August 31, 2001.

<TABLE>
<CAPTION>
SIGNATURE                                       TITLE
---------                                       -----

<S>                                             <C>
/s/ Homer A. Scott, Jr.                         Chairman of the Board
----------------------------------------
Homer A. Scott, Jr.

/s/ Dan S. Scott                                Director
----------------------------------------
Dan S. Scott

/s/ James R. Scott                              Vice Chairman of the Board
----------------------------------------
James R. Scott

/s/ Sandra Scott Suzor                          Director
Sandra Scott Suzor

/s/ John M. Heyneman, Jr.                       Director
----------------------------------------
John M. Heyneman, Jr.

/s/ Joel T. Long                                Director
----------------------------------------
Joel T. Long

/s/ Lyle R. Knight                              President and Chief Operating Officer, Director
----------------------------------------
Lyle R. Knight

/s/ Terry W. Payne                              Director
----------------------------------------
Terry W. Payne

/s/ James Haugh                                 Director
James Haugh

/s/ Thomas W. Scott                             Chief Executive Officer and Director
----------------------------------------        (Principal Executive Officer)
Thomas W. Scott

/s/ C. Gary Jennings                            Director
----------------------------------------
C. Gary Jennings

/s/ Robert L. Nance                             Director
----------------------------------------
Robert L. Nance
</TABLE>




                                       9

<PAGE>   10


<TABLE>
<S>                                             <C>


/s/ Robert H. Waller                            Director
----------------------------------------
Robert H. Waller

/s/ Elouise C. Cobell                           Director
----------------------------------------
Elouise C. Cobell

/s/ Richard A. Dorn                             Director
----------------------------------------
Richard A. Dorn

/s/ Larry F. Suchor                             Director
----------------------------------------
Larry F. Suchor

/s/ William B. Ebzery                           Director
----------------------------------------
William B. Ebzery

/s/ David H. Crum                               Director
----------------------------------------
David H. Crum

/s/ Terrill R. Moore                            Senior Vice President, Chief Financial Officer
----------------------------------------        (Principal Financial and Accounting Officer)
Terrill R. Moore
</TABLE>





                                       10


<PAGE>   11


                        FIRST INTERSTATE BANCSYSTEM, INC.

                                 EXHIBITS INDEX

<TABLE>
<CAPTION>
      Exhibit                                                   Document
      -------                                                   --------
      <S>                  <C>
       4.1(1)              Restated Articles of Incorporation of the Registrant dated February 27, 1986

       4.2(2)              Articles of Amendment to Restated Articles of Incorporation of the Registrant dated
                           September 19, 1996

       4.3(2)              Articles of Amendment to Restated Articles of Incorporation of the Registrant dated
                           September 19, 1996

       4.4(3)              Articles of Amendment to Restated Articles of Incorporation of the Registrant dated
                           October 7, 1997

       4.5(3)              Bylaws of the Registrant

       4.5(4)              Amendment to Bylaws of the Registrant dated March 18, 1999

       4.6                 Amendment to Bylaws of the Registrant dated May 18, 2001

       4.7(5)              Specimen of common stock certificate of First Interstate BancSystem, Inc.

       4.8(1)              Shareholder's Agreement for non-Scott family members

       4.9(7)              Shareholder's Agreement for non-Scott family members dated August 24, 2001

       4.8                 2001 Stock Option Plan of the Registrant

       4.9(6)              First Interstate Stockholders' Agreements with Scott family members

       5                   Opinion of Holland & Hart LLP, as to the legality of securities being registered.

       23.1                Consent of KPMG LLC, Independent Certified Public Accountants

       23.2                Consent of Holland & Hart LLP (contained in Exhibit 5)

       24                  Power of Attorney (included on page 10 of this Registration Statement)
</TABLE>


                     * * * * * * * * * * * * * * * * * * * *

(1)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-1, No. 333-84540.

(2)      Incorporated by reference to the Registrant's Form 8-K dated October 1,
         1996.

(3)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-1, No. 333-37847.

(4)      Incorporated by reference to the Registrant's Form 10-K for the fiscal
         year ended December 31, 1999, No. 033-64304.

(5)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-1, No. 333-3250.

(6)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-8, No. 333-76825.

(7)      Incorporated by reference to the Registrant's Post-Effective Amendment
         No. 1 to Registration Statement on Form S-8, No. 333-76825



                                       11
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{"company-data": {"conformed-name": "FIRST INTERSTATE BANCSYSTEM INC", "cik": "0000860413", "assigned-sic": "6022", "irs-number": "810331430", "state-of-incorporation": "MT", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-69490", "film-number": "1738682"}, "business-address": {"street1": "P O BOX 30918", "street2": "401 NO 31ST STREET", "city": "BILLINGS", "state": "MT", "zip": "59116-0918", "phone": "4062555300"}, "former-company": {"former-conformed-name": "FIRST INTERSTATE BANCSYSTEM OF MONTANA INC", "date-changed": "19930615"}}
1

   As filed with the Securities and Exchange Commission on September 17, 2001

================================================================================

                              Registration No. 333-

                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                                    --------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                        FIRST INTERSTATE BANCSYSTEM, INC.
               --------------------------------------------------
               (Exact name of issuer as specified in its charter)

           MONTANA                                             81-0331430
-------------------------------                          ----------------------
(State or other Jurisdiction of                            (I.R.S. Employer
incorporation or organization)                           Identification Number)

                 400 North 31st Street, Billings, Montana 59116
              -----------------------------------------------------
              (Address of Principal Executive Offices and Zip Code)

            FIRST INTERSTATE BANCSYSTEM, INC. 2001 STOCK OPTION PLAN
            --------------------------------------------------------
                              (Full title of plan)

                                Terrill R. Moore
                Senior Vice President and Chief Financial Officer
                        FIRST INTERSTATE BANCSYSTEM, INC.
                              401 North 31st Street
                             Billings, Montana 59116
                -------------------------------------------------
                     (Name and address of agent for service)

                                 (406) 255-5300
          -------------------------------------------------------------
          (Telephone number, including area code, of agent for service)

                                  With Copy to:
                               Holland & Hart LLP
                          Attn: Dennis M. Jackson, Esq.
                       555 Seventeenth Street, Suite 3200
                             Denver, Colorado 80202
                                 (303) 295-8115

                         CALCULATION OF REGISTRATION FEE
----------------------------------------------------------------------------------------------------------------------
                                                        Proposed                Proposed
Title of Securities to        Amount to be          maximum offering        maximum aggregate          Amount of
be registered                registered (1)        price per share(2)        offering price        registration fee
----------------------------------------------------------------------------------------------------------------------
Common Stock
(no par value)                   750,000                 $40.00                $30,000,000              $7,500
----------------------------------------------------------------------------------------------------------------------
(1)      Pursuant to Rule 416(a) under the Securities Act of 1933, as amended
         (the "Securities Act"), this Registration Statement shall also cover
         any additional shares of the Registrant's Common Stock, no par value,
         which are issued or become issuable under the First Interstate
         BancSystem, Inc. 2001 Stock Option Plan.

(2)      Calculated in accordance with Rule 457(h) under the Securities Act,
         based upon the latest appraised value of $40.00 per share for 750,000
         shares reserved for issuance under the First Interstate BancSystem,
         Inc. 2001 Stock Option Plan.

================================================================================
2

                                     PART I

              INFORMATION REQUIRED IN THE SECTION (10(A) PROSPECTUS

         The documents containing the information required by Part I of Form S-8
will be sent or given to participants in the First Interstate BancSystem, Inc.
Stock Option Plan (the "Plan") as specified by Rule 428(b)(1) under the
Securities Act. In reliance on Rule 428, such documents (i) are not being filed
with the Securities and Exchange Commission (the "Commission") either as part of
this registration statement or as prospectuses or prospectus supplements
pursuant to Rule 424, and (ii) along with the documents incorporated by
reference into this registration statement pursuant to Item 3 of Part II hereof,
constitute a prospectus (the "Prospectus") that meets the requirements of
Section 10(a) of the Securities Act.

                                     PART II

Item 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

         The following documents filed by First Interstate BancSystem, Inc. (the
"Registrant") with the Securities and Exchange Commission are hereby
incorporated by reference in this Registration Statement:

         (a) The Registrant's latest Annual Report, filed pursuant to Section
15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"),
on Form 10-K, for the fiscal year ended December 31, 2000.

         (b) The Registrant's Quarterly Report on Form 10-Q for the three months
ended March 31, 2001.

         (c) The Registrant's Quarterly Report on Form 10-Q for the three and
six months ended June 30, 2001.

         (d) The Registrant's amended Annual Reports, filed pursuant to Section
15(d) of the Securities Exchange Act of 1934 (the "Exchange Act"), on Form
10-K/A for the fiscal years ended December 31, 1997, 1998 and 1999.

         (e) The Registrant's amended Quarterly Reports, for the three-month
periods ended on March 31, June 30 and September 30 of each of 1997, 1998 and
1999, on Form 10-Q/A.

         (f) The Registrant's Current Reports on Form 8-K filed on June 1, 2001
and July 20, 2001 and Registrant's amended Current Report on Form 8-K/A filed on
June 8, 2001.

         (g) All documents filed subsequent hereto by the Registrant, pursuant
to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing
of a post-effective amendment which indicates that all securities offered have
been sold or which deregisters all securities then remaining unsold.

Item 4.  DESCRIPTION OF SECURITIES.

         The authorized capital stock of the Registrant consists of 20,000,000
shares of common stock without par value (the "Common Stock"), of which
7,830,303 shares were outstanding as of July 31, 2001, and 100,000 shares of
preferred stock without par value, none of which were outstanding as of July 31,
2001.

                                       2
3

COMMON STOCK

         Each share of the Common Stock is entitled to one vote in the election
of directors and in all other matters submitted to a vote of shareholders.
Accordingly, holders of a majority of the shares of Common Stock entitled to
vote in any election of directors may elect all of the directors standing for
election if they choose to do so, subject to the rights of the holders of the
preferred stock. Voting for directors is noncumulative.

         Subject to the preferential rights of any preferred stock that may at
the time be outstanding, each share of Common Stock has an equal and ratable
right to receive dividends when, if and as declared by the Board of Directors
out of assets legally available therefor. In the event of a liquidation,
dissolution or winding up of the Company, the holders of Common Stock will be
entitled to share equally and ratably in the assets available for distribution
after payments to creditors and to the holders of any preferred stock that may
at the time be outstanding. Holders of Common Stock have no conversion rights or
preemptive or other rights to subscribe for any additional shares of Common
Stock or for other securities. All outstanding Common Stock is fully paid and
non-assessable.

         The Common Stock of the Company is not actively traded, and there is no
established trading market for the stock. There is only one class of Common
Stock, with approximately 92% of the shares subject to contractual transfer
restrictions set forth in one of four shareholder agreements and approximately
8% held by 13 shareholders without such restrictions. The Company has the right
of first refusal to purchase the restricted stock at fair market value per share
("Fair Market Value") determined as follows: (i) if the Common Stock is listed
on any established stock exchange or a national market system, fair market value
shall be the closing sales price for the Common Stock as quoted on such exchange
or system for the last market trading day prior to the date of determination;
(ii) if the Common Stock is regularly quoted by a recognized securities dealer
but selling prices are not reported, fair market value shall be the mean between
the high bid and the low asked prices for the Common Stock on the last market
trading day prior to the date of determination; or (iii) in the absence of an
established market for the Common Stock, fair market value shall be determined
in good faith by the Board which may, in its sole discretion, utilize an
independent third party to assist with the determination of the fair market
value, which may take the form of a periodic appraisal of the fair market value
of a share of Common Stock valued as a minority interest. The appraised minority
value of the Common Stock represents the estimated fair market valuation of a
minority block of such stock, taking into account adjustments for the lack of
marketability of the stock and other factors. This value does not represent an
actual trading price between a willing buyer and seller of the Common Stock in
an informed, arm's-length transaction. As such, the appraised minority value is
only an estimate as of a specific date, and there can be no assurance that such
appraisal is an indication of the actual value holders of the Common Stock may
realize with respect to shares held by them. Moreover, the estimated fair market
value of the Common Stock may be materially different at any date other than the
valuation dates indicated above.

         All stock not subject to such restrictions may be sold at a price per
share that is acceptable to the shareholder.

         Resale of the Common Stock may be restricted pursuant to the Securities
Act and applicable state securities laws. In addition, most shares of the Common
Stock are subject to one of four shareholders' agreements. Members of the Scott
family, as majority shareholders of the Company, are subject to a shareholder's
agreement (the "Scott Agreement"). The Scott family, under the Scott Agreement,
has agreed to limit the transfer of shares owned by members of the Scott family
to family members or charities, or with the Company's approval, to the Company's
officers, directors (including advisory directors), employees, or to the
Company's Savings and Profit Sharing Plan for Employees of First Interstate
BancSystem, Inc. (the "Savings Plan").

         Shareholders of the Company who are not Scott family members, with the
exception of 13 shareholders who own an aggregate of approximately 600,000
shares of unrestricted stock, are subject to one of three shareholder's
agreements. Shares of Common Stock hereby offered to Participants who are not
Scott family members are subject to execution of the shareholder's agreement
dated August 24, 2001 (the "2001 Shareholder's Agreement"). Upon execution of
the 2001 Shareholder's Agreement, all previous shareholder's agreements,
including the Shareholder's Agreement described below, shall be

                                       3
4

superceded. The 2001 Shareholder's Agreement grants the Company the right to
acquire some or all of the Common Stock at any time at the Fair Market Value of
the Common Stock. Common Stock subject to the 2001 Shareholder's Agreement may
not be sold or transferred by the shareholder without triggering the Company's
first right of refusal to acquire the stock.

         Charities that received gifts of Common Stock from existing
shareholders prior to August 1, 2001 are subject to a restrictive shareholder's
agreement, which gives the Company the right to repurchase the stock in any of
the following events: 1) the charity's intention to sell the stock, 2) transfer
of the stock by operation of law, and 3) at any other time as determined by the
Company. Charities receiving gifts of stock subsequent to August 1, 2001 will be
subject to the 2001 Shareholder's Agreement.

         Prior to execution of the 2001 Shareholder's Agreement, shareholders of
the Company who are not Scott family members or charities, with the exception of
13 shareholders owning unrestricted stock, are subject to a different form of
shareholder's agreement (the "Shareholder's Agreement"). The Shareholder's
Agreement grants the Company the option to purchase Common Stock in any of the
following events: 1) the shareholder's intention to sell the stock, 2) the
shareholder's death, 3) transfer of the stock by operation of law, 4)
termination of the shareholder's status as a director, officer or employee of
the Company, and 5) total disability of the shareholder. Stock subject to the
Shareholder's Agreement may not be sold or transferred by the shareholder
without triggering the Company's option to acquire the stock in accordance with
the terms of the Shareholder's Agreement. In addition, the Shareholder's
Agreement allows the Company to repurchase any of the Common Stock acquired by
the shareholder after January 1, 1994 if the Company determines that the number
of shares owned by the shareholder is excessive in view of a number of factors,
including, but not limited, to (a) the relative contribution of the shareholder
to the economic performance of the Company, (b) the effort being put forth by
the shareholder, and (c) the level of responsibility of the shareholder.

         The Trust Department of First Interstate Bank in Montana ("FIB
Montana"), a subsidiary of the Company (the "Savings Plan Trustee"), is the
Trustee of the Savings Plan. The Savings Plan Trustee owns shares of Common
Stock which are allocated to the accounts of participants in the Savings Plan
and votes the shares based on the instructions of each participant therein. In
the event a participant does not provide the Savings Plan Trustee with
instructions, the Savings Plan Trustee will vote the shares allocated to such
Participant in accordance with voting instructions received from a majority of
the participants in the Savings Plan. The Savings Plan Trustee receives
reasonable compensation for its service as such.

         Purchases of the Common Stock made through the Savings Plan are not
restricted by any shareholder's agreement, due to requirements of ERISA and the
Code. However, since the Savings Plan does not allow distributions "in kind,"
any distributions from an employee's account in the Savings Plan will allow, and
may require, the Savings Plan Trustee to sell the Common Stock. While the
Company has no obligation to repurchase the Common Stock, it is possible that
the Company will repurchase the Common Stock sold out of the Savings Plan. Any
such repurchases would be upon terms set by the Savings Plan Trustee and
accepted by the Company.

DIVIDENDS

         It is the policy of the Company to pay a dividend to all holders of the
Common Stock on a quarterly basis. Dividends are declared and paid in the month
following the calendar quarter and the amount has historically been determined
based upon a percentage of net income for the calendar quarter immediately
preceding the dividend payment date. Effective with the dividend for the fourth
quarter of 1995 paid in January 1996, the dividend has been 30% of quarterly net
income without taking into effect compensation expense related to stock options.
The Board of Directors of the Company has no current intention to change its
dividend policy, but no assurance can be given that the Board may not, in the
future, change or eliminate the payment of dividends.

                                       4
5

DIVIDEND RESTRICTIONS

         The holders of Common Stock will be entitled to dividends when, as and
if declared by the Company's Board of Directors out of funds legally available
therefor. As a holding company, the Company is a corporation separate and apart
from its bank subsidiaries, FIB Montana and First Interstate Bank in Wyoming
(together, the "Banks"). The Company's ability to pay dividends to its
stockholders is dependent upon the cash dividend payments received by the
Company from the Banks. Dividend payments from the Banks are subject to federal
and state banking limitations, generally based on current and retained earnings,
imposed by the various federal and state regulatory agencies with authority over
the respective Banks. Payment of dividends by the Banks is also subject to each
respective Bank's profitability, financial condition, capital expenditures and
cash flow requirements. Payment of dividends may also be restricted by
applicable banking regulations if such dividends would impair the capital of the
respective Banks or constitute an "unsafe or unsound" practice. In addition,
there are restrictions and financial covenants in the Company's debt instruments
which may prohibit the payment of dividends from the Banks to the Company and
from the Company to its stockholders in certain circumstances.

PREFERRED STOCK

         The authorized capital stock of the Company includes 100,000 shares of
preferred stock. The Company's Board of Directors is authorized, without
approval of the holders of the Common Stock, to provide for the issuance of
preferred stock from time to time in one or more series in such number and with
such designations, preferences, powers and other special rights as may be stated
in the resolution or resolutions providing for such preferred stock. The
Company's Board of Directors may cause the Company to issue preferred stock with
voting, conversion and other rights that could adversely affect the holders of
the Common Stock by making it more difficult to effect a change in control of
the Company.

         In the event of any dissolution, liquidation or winding up of the
affairs of the Company, before any distribution or payment may be made to the
holders of the Common Stock, the holders of preferred stock would be entitled to
be paid in full with the respective amounts fixed by the Company's Board of
Directors in the resolution or resolutions authorizing the issuance of such
series, together with a sum equal to the accrued and unpaid dividends thereon to
the date fixed for such distribution or payment. After payment in full of the
amount which the holders of preferred stock are entitled to receive, the
remaining assets of the Company would be distributed ratably to the holders of
the Common Stock. If the assets available are not sufficient to pay in full the
amount so payable to the holders of all outstanding preferred stock, the holders
of all series of such shares would share ratably in any distribution of assets
in proportion to the full amounts to which they would otherwise be respectively
entitled. The consolidation or merger of the Company into or with any other
corporation or corporations would not be deemed a liquidation, dissolution, or
winding up of the affairs of the Company.

Item 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL

         Not Applicable

Item 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Officers and directors of the Registrant are entitled to
indemnification under the Montana Business Corporation Act and pursuant to a
Resolution of the Board of Directors of the Registrant dated January 12, 1987. A
summary of the indemnification provision in such resolution follows:

         Pursuant to a resolution of the Board of Directors dated January 12,
1987, and under the authority of Section 35-1-414 of the Montana Business
Corporation Act, the Registrant shall indemnify each director and officer of the
Registrant (including former officers and directors) and each agent of the
Registrant serving as a director or officer of a Bank, serving at the specific
direction or request of the Registrant (but only to the extent that such
director, officer or agent is not indemnified by the Bank or by insurance
provided by the Registrant) against judgments, penalties, fines, settlements and
reasonable expenses actually and reasonably paid by such director, officer or
agent by reason of the fact that he or she is or was a director or officer of
the Registrant or such Bank, to the extent provided by and subject to the
limitations of the Montana Business Corporation Act.

                                       5
6

         Officers and directors of the Registrant are also entitled to
indemnification under the Registrant's Bylaws, a copy of which is included as an
exhibit hereto.

Item 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         Not Applicable.

Item 8.  EXHIBITS
Regulation S-K
         Exhibit                                                   Document
     --------------                                                --------
4.1(1)              Restated Articles of Incorporation of the Registrant dated February 27, 1986

       4.2(2)              Articles of Amendment to Restated Articles of Incorporation of the Registrant dated
                           September 19, 1996

       4.3(2)              Articles of Amendment to Restated Articles of Incorporation of the Registrant dated
                           September 19, 1996

       4.4(3)              Articles of Amendment to Restated Articles of Incorporation of the Registrant dated
                           October 7, 1997

       4.5(3)              Bylaws of the Registrant

       4.5(4)              Amendment to Bylaws of the Registrant dated March 18, 1999

       4.6                 Amendment to Bylaws of the Registrant dated May 18, 2001

       4.7(5)              Specimen of common stock certificate of First Interstate BancSystem, Inc.

       4.8(1)              Shareholder's Agreement for non-Scott family members

       4.9(7)              Shareholder's Agreement for non-Scott family members dated August 24, 2001

       4.8                 2001 Stock Option Plan of the Registrant

       4.9(6)              First Interstate Stockholders' Agreements with Scott family members

       5                   Opinion of Holland & Hart LLP, as to the legality of securities being registered.

       23.1                Consent of KPMG LLC, Independent Certified Public Accountants

       23.2                Consent of Holland & Hart LLP (contained in Exhibit 5)

       24                  Power of Attorney (included on page 10 of this Registration Statement)
* * * * * * * * * * * * * * * * * * * *

(1)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-1, No. 333-84540.

(2)      Incorporated by reference to the Registrant's Form 8-K dated October 1,
         1996.

                                       6
7

(3)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-1, No. 333-37847.

(4)      Incorporated by reference to the Registrant's Form 10-K for the fiscal
         year ended December 31, 1999, No. 033-64304.

(5)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-1, No. 333-3250.

(6)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-8, No. 333-76825.

(7)      Incorporated by reference to the Registrant's Post-Effective Amendment
         No. 1 to Registration Statement on Form S-8, No. 333-76825

Item 9.  UNDERTAKINGS

         (a) The undersigned Registrant hereby undertakes:

                  (1)      To file, during any period in which offers or sales
                           are being made, a post-effective amendment to this
                           registration statement:

                           (i)      To include any prospectus required by
                                    Section 10(a)(3) of the Securities Act;

                           (ii)     To reflect in the prospectus any facts or
                                    events arising after the effective date of
                                    the registration statement (or the most
                                    recent post-effective amendment thereof)
                                    which, individually or in the aggregate,
                                    represent a fundamental change in the
                                    information set forth in the registration
                                    statement;

                           (iii)    To include any material information with
                                    respect to the plan of distribution not
                                    previously disclosed in the registration
                                    statement or any material change to such
                                    information in the registration statement;

                           provided, however, that paragraphs (a)(1)(i) and
                           (a(1)(ii) do not apply if the registration statement
                           is on Form S-3 or Form S-8, and the information
                           required to be included in a post-effective amendment
                           by those paragraphs is contained in periodic reports
                           filed with or furnished to the Commission by the
                           Registrant pursuant to Section 13 or Section 15(d) of
                           the Exchange Act that are incorporated by reference
                           in the registration statement.

                  (2)      That, for the purpose of determining any liability
                           under the Securities Act, each such post-effective
                           amendment shall be deemed to be a new registration
                           statement relating to the securities offered therein,
                           and the offering of such securities at that time
                           shall be deemed to be the initial bona fide offering
                           thereof.

                  (3)      To remove from the registration by means of a
                           post-effective amendment any of the securities being
                           registered which remain unsold at the termination of
                           the offering.

         (b)      The undersigned Registrant hereby undertakes that, for
                  purposes of determining any liability under the Securities
                  Act, each filing of the Registrant's annual report pursuant to
                  Section 13(a) or Section 15(d) of the Exchange Act that is
                  incorporated by reference in this registration statement shall
                  be deemed to be a new registration statement relating to the
                  securities offered therein, and the offering of such
                  securities at that time shall be deemed to be the initial bona
                  fide offering thereof.

                                       7
8

         (c)      Insofar as indemnification for liabilities arising under the
                  Securities Act may be permitted to directors, officers and
                  controlling persons of the Registrant pursuant to the
                  foregoing provisions, or otherwise, the Registrant has been
                  advised that in the opinion of the Securities and Exchange
                  Commission such indemnification is against public policy as
                  expressed in the Securities Act and is, therefore,
                  unenforceable. In the event that a claim for indemnification
                  against such liabilities (other than the payment by the
                  Registrant of expenses incurred or paid by a director, officer
                  or controlling person of the Registrant in the successful
                  defense of any action, suit or proceeding) is asserted by such
                  director, officer or controlling person in connection with the
                  securities being registered, the Registrant will, unless in
                  the opinion of its counsel the matter has been settled by
                  controlling precedent, submit to a court of appropriate
                  jurisdiction the question whether such indemnification by it
                  is against public policy as expressed in the Securities Act
                  and will be governed by the final adjudication of such issue.

                                   SIGNATURES

1.       REGISTRANT

         Pursuant to the requirements of the Securities Act, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Billings, State of Montana, on August 31, 2001.

                                       First Interstate BancSystem, Inc.

                                       By: /s/ Thomas W. Scott
                                           -------------------------------------
                                           Thomas W. Scott
                                           President and Chief Executive Officer

                                       8
9

                                POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature to
this Registration Statement appears below hereby constitutes and appoints Thomas
W. Scott and Terrill R. Moore, and each of them, as his true and lawful
attorney-in-fact and agent, with full power of substitution, to sign on his
behalf individually and in the capacity stated below, and to perform any acts
necessary to be done in order to file all amendments and post-effective
amendments to this Registration Statement, and any and all instruments or
documents filed as part of or in connection with this Registration Statement or
the amendments thereto and each of the undersigned does hereby ratify and
confirm all that such attorney-in-fact and agent, or his substitutes, shall do
or cause to be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, the
Registration Statement has been signed below by the following persons in the
capacities indicated on August 31, 2001.
SIGNATURE                                       TITLE
---------                                       -----
/s/ Homer A. Scott, Jr.                         Chairman of the Board
----------------------------------------
Homer A. Scott, Jr.

/s/ Dan S. Scott                                Director
----------------------------------------
Dan S. Scott

/s/ James R. Scott                              Vice Chairman of the Board
----------------------------------------
James R. Scott

/s/ Sandra Scott Suzor                          Director
Sandra Scott Suzor

/s/ John M. Heyneman, Jr.                       Director
----------------------------------------
John M. Heyneman, Jr.

/s/ Joel T. Long                                Director
----------------------------------------
Joel T. Long

/s/ Lyle R. Knight                              President and Chief Operating Officer, Director
----------------------------------------
Lyle R. Knight

/s/ Terry W. Payne                              Director
----------------------------------------
Terry W. Payne

/s/ James Haugh                                 Director
James Haugh

/s/ Thomas W. Scott                             Chief Executive Officer and Director
----------------------------------------        (Principal Executive Officer)
Thomas W. Scott

/s/ C. Gary Jennings                            Director
----------------------------------------
C. Gary Jennings

/s/ Robert L. Nance                             Director
----------------------------------------
Robert L. Nance
9
10
/s/ Robert H. Waller                            Director
----------------------------------------
Robert H. Waller

/s/ Elouise C. Cobell                           Director
----------------------------------------
Elouise C. Cobell

/s/ Richard A. Dorn                             Director
----------------------------------------
Richard A. Dorn

/s/ Larry F. Suchor                             Director
----------------------------------------
Larry F. Suchor

/s/ William B. Ebzery                           Director
----------------------------------------
William B. Ebzery

/s/ David H. Crum                               Director
----------------------------------------
David H. Crum

/s/ Terrill R. Moore                            Senior Vice President, Chief Financial Officer
----------------------------------------        (Principal Financial and Accounting Officer)
Terrill R. Moore
10
11

                        FIRST INTERSTATE BANCSYSTEM, INC.

                                 EXHIBITS INDEX
Exhibit                                                   Document
      -------                                                   --------
4.1(1)              Restated Articles of Incorporation of the Registrant dated February 27, 1986

       4.2(2)              Articles of Amendment to Restated Articles of Incorporation of the Registrant dated
                           September 19, 1996

       4.3(2)              Articles of Amendment to Restated Articles of Incorporation of the Registrant dated
                           September 19, 1996

       4.4(3)              Articles of Amendment to Restated Articles of Incorporation of the Registrant dated
                           October 7, 1997

       4.5(3)              Bylaws of the Registrant

       4.5(4)              Amendment to Bylaws of the Registrant dated March 18, 1999

       4.6                 Amendment to Bylaws of the Registrant dated May 18, 2001

       4.7(5)              Specimen of common stock certificate of First Interstate BancSystem, Inc.

       4.8(1)              Shareholder's Agreement for non-Scott family members

       4.9(7)              Shareholder's Agreement for non-Scott family members dated August 24, 2001

       4.8                 2001 Stock Option Plan of the Registrant

       4.9(6)              First Interstate Stockholders' Agreements with Scott family members

       5                   Opinion of Holland & Hart LLP, as to the legality of securities being registered.

       23.1                Consent of KPMG LLC, Independent Certified Public Accountants

       23.2                Consent of Holland & Hart LLP (contained in Exhibit 5)

       24                  Power of Attorney (included on page 10 of this Registration Statement)
* * * * * * * * * * * * * * * * * * * *

(1)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-1, No. 333-84540.

(2)      Incorporated by reference to the Registrant's Form 8-K dated October 1,
         1996.

(3)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-1, No. 333-37847.

(4)      Incorporated by reference to the Registrant's Form 10-K for the fiscal
         year ended December 31, 1999, No. 033-64304.

(5)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-1, No. 333-3250.

(6)      Incorporated by reference to the Registrant's Registration Statement on
         Form S-8, No. 333-76825.

(7)      Incorporated by reference to the Registrant's Post-Effective Amendment
         No. 1 to Registration Statement on Form S-8, No. 333-76825

                                       11