<DOCUMENT>
<TYPE>EX-21.1
<SEQUENCE>5
<FILENAME>c75527exv21w1.txt
<DESCRIPTION>EX-21.1 SUBSIDIARIES
<TEXT>
<PAGE>
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                                                                    EXHIBIT 21.1


                SUBSIDIARIES OF FIRST INTERSTATE BANCSYSTEM, INC.

<TABLE>
<CAPTION>

                                              State of Incorporation or
    Subsidiary                              Jurisdiction of Organization                Business Name
-------------------------------------------------------------------------------------------------------------
<S>                                      <C>                                       <C>
First Interstate Bank                                  Montana                      First Interstate Bank

Commerce Financial, Inc.                               Montana                      Commerce Financial, Inc.

FIB Capital Trust                                     Delaware                      FIB Capital Trust

i_Tech Corporation                                     Montana                      i_Tech Corporation

FIB, LLC                                               Montana                      FIB, LLC

FI Reinsurance, Ltd.                          Nevis Island, West Indies             FI Reinsurance, Ltd.

</TABLE>


</TEXT>
</DOCUMENT>