First Interstate BancSystem, Inc. Announces Second Quarter Earnings Release and Conference Call

First Interstate BancSystem, Inc. (NASDAQ: FIBK), parent company of First Interstate Bank, will report second quarter financial results after the market closes on July 25, 2011. A conference call for investors is scheduled for Tuesday, July 26, 2011 at 11:00a.m. Eastern Time (9:00a.m. MT), during which the Company will discuss second quarter 2011 results. There will be a question and answer session following the presentation.

The conference call will be accessible by telephone and through the Internet. Shareholders, analysts, and other interested parties are invited to join the call by dialing 1-877-317-6789. To participate via the Internet, log on to www.fibk.com. A rebroadcast will be available approximately one hour after the end of the conference call by dialing 1-877-344-7529. The conference ID is 10001664. The call will also be archived on our Web site, www.fibk.com.

First Interstate BancSystem, Inc. is a financial services holding company, headquartered in Billings, Montana, with $7.4 billion in assets as of March 31, 2011. It is the parent company of First Interstate Bank, a community bank operating 71 offices throughout Montana, Wyoming, and western South Dakota. As a recognized leader in community banking services with 23 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.