8-K

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): September 2, 2010

FIRST INTERSTATE BANCSYSTEM, INC.

(Exact name of registrant as specified in its charter)

Montana	001-34653	81-0331430
(State or other jurisdiction of incorporation or organization)	(Commission File No.)	(IRS Employer Identification No.)

401 North 31^st Street, Billings, MT
(Address of principal executive offices)

(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 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 8.01 Other Events.

     On September 2, 2010, First Interstate BancSystem, Inc. (the “Registrant”) issued a press release announcing the appointment of Robert M. Cerkovnik as Senior Vice President and Chief Credit Officer.

Item 9.01 Financial Statements and Exhibits.

     (d) Exhibit 99.1 — Press Release dated September 2, 2010 announcing the appointment of Robert M. Cerkovnik as Senior Vice President and Chief Credit Officer.

SIGNATURE

     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: September 2, 2010

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

EX-99.1

Exhibit 99.1

First Interstate BancSystem, Inc. Appoints New Chief Credit Officer

Company Release: September 2, 2010

(Billings, Montana) First Interstate BancSystem, Inc. (NASDAQ: FIBK), announced today that Robert M. Cerkovnik has accepted the position of Senior Vice President and Chief Credit Officer.

Cerkovnik has been a senior vice president with First Interstate since February 2008 and has served as a Senior Credit Officer and Credit Department Manager since February 2003. Prior to joining the First Interstate management team, he worked in various credit-related positions since September 1996. Cerkovnik has more than 25 years of experience in the banking industry, previously serving as a bank examiner for the Comptroller of the Currency and in credit and lending positions with two national banks.

First Interstate BancSystem, Inc. is a financial services holding company, headquartered in Billings, Montana, with $7.2 billion in assets as of June 30, 2010. It is the parent company of First Interstate Bank, a community bank operating 72 offices throughout Montana, Wyoming and western South Dakota. As a recognized leader in community banking services with 22 consecutive years of profitability, First Interstate remains a family business whose culture is driven by strong family and corporate values, as well as a commitment to long-term organic growth, exemplary customer service, exceeding customer expectations through its products and services and supporting with leadership and resources, the communities it serves.

Contact:
Marcy Mutch
Investor Relations
First Interstate BancSystem, Inc.
401 North 31st Street
Billings, Montana 59116
+1 406-255-5322
investor.relations@fib.com