UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington D.C. 20549

FORM 8-K

CURRENT REPORT
Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of report (date of earliest event reported): February 8, 2010

FIRST INTERSTATE BANCSYSTEM, INC.

(Exact name of registrant as specified in its charter)

Montana	000-49733	81-0331430
(State or other jurisdiction of incorporation or organization)	(Commission File No.)	(IRS Employer Identification No.)

401 North 31^st Street, Billings, MT 59116

(Address of principal executive offices, including zip code)

(406) 255-5390

(Registrant’s telephone number, including area code)

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o      Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o      Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o      Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o      Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 2.02 Results of Operations and Financial Condition.

On February 8, 2010, First Interstate BancSystem, Inc. (the “Registrant”) issued its fourth quarter 2009 performance report (“Performance Report”) to holders of common stock of the Registrant as of that date.

The Performance Report is attached as Exhibit 99 to this Current Report on Form 8-K.

Item 7.01 Regulation FD Disclosure.

The information furnished under Item 2.02 is also being furnished under this Item 7.01.

Item 9.01 Financial Statements and Exhibits.

(c) Exhibit 99 — Fourth Quarter 2009 Performance Report

SIGNATURES

     Pursuant to the requirements of the Securities and Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Dated: February 8, 2010

FIRST INTERSTATE BANCSYSTEM, INC.
By:	/s/ LYLE R. KNIGHT
	Lyle R. Knight
	President and Chief Executive Officer