First Midwest Bancorp, Inc. is a bank holding company headquartered in the Chicago suburb of Itasca, Illinois with operations throughout the greater Chicago suburban area as well as central and western Illinois. Our principal subsidiary is First Midwest Bank, which provides a broad range of commercial and retail banking services to consumer, commercial and industrial, and public or governmental customers. We are committed to meeting the financial needs of the people and businesses in the communities where we live and work by providing customized banking solutions, quality products, and innovative services that truly fulfill those financial needs.

We file annual, quarterly, and current reports, proxy statements and other information with the Securities and Exchange Commission ("SEC"), and we make this information available free of charge on or through the investor relations section of our web site at www.firstmidwest.com/aboutinvestor_overview.asp. The following are also posted on our web site or available in print upon the request of any stockholder to our Corporate Secretary:

Within the time period required by the SEC and the Nasdaq Stock Market, we will post on our web site any amendment to the Code and any waiver applicable to any executive officer, director, or senior financial officer (as defined in the Code). In addition, our web site includes information concerning purchases and sales of our securities by our executive officers and directors, as well as any disclosure relating to certain non-GAAP financial measures (as defined in the SEC's Regulation G) that we may make public orally, telephonically, by webcast, by broadcast, or by similar means from time to time.

Our Corporate Secretary can be contacted by writing to First Midwest Bancorp, Inc., One Pierce Place, Itasca, Illinois 60143, Attn: Corporate Secretary. The Company's Investor Relations Department can be contacted by telephone at (630) 875-7463 or by e-mail at investor.relations@firstmidwest.com.

CAUTIONARY STATEMENT PURSUANT TO THE PRIVATE SECURITIES
LITIGATION REFORM ACT OF 1995

We include or incorporate by reference in this Quarterly Report on Form 10-Q, and from time to time our management may make, statements that may constitute "forward-looking statements" within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These statements are not historical facts, but instead represent only management's beliefs regarding future events, many of which, by their nature, are inherently uncertain and outside our control. Although we believe the expectations reflected in any forward-looking statements are reasonable, it is possible that our actual results and financial condition may differ, possibly materially, from the anticipated results and financial condition indicated in such statements. In some cases, you can identify these statements by forward-looking words such as "may," "might," "will," "should," "expect," "plan," "anticipate," "believe," "estimate," "predict," "potential," or "continue," and the negative of these terms and other comparable terminology. We caution you not to place undue reliance on forward-looking statements, which speak only as of the date of this report, or when made.

Forward-looking statements are subject to known and unknown risks, uncertainties, and assumptions and may include projections relating to our future financial performance including our growth strategies and anticipated trends in our business. For a detailed discussion of these and other risks and uncertainties that could cause actual results and events to differ materially from such forward-looking statements, you should refer to our Annual Report on Form 10-K for the year ended December 31, 2007, including the sections entitled "Risk Factors" and "Management's Discussion and Analysis of Results of Operations," as well as our subsequent periodic and current reports, filed with the SEC. These risks and uncertainties are not exhaustive however. Other sections of this report describe additional factors that could adversely impact our business and financial performance. Moreover, we operate in a very competitive and rapidly changing environment. New risks and uncertainties emerge from time to time, and it is not possible to predict all risks and uncertainties, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements. We are under no duty to update any of these forward-looking statements after the date of this report to conform our prior statements to actual results or revised expectations, and we do not intend to do so.

3

4

5

6

7

The accompanying unaudited consolidated interim financial statements of First Midwest Bancorp, Inc. (the "Company"), a Delaware corporation, have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission for quarterly reports on Form 10-Q and do not include certain information and footnote disclosures required by U.S. generally accepted accounting principles ("GAAP") for complete annual financial statements. Accordingly, these financial statements should be read in conjunction with the Company's 2007 Annual Report on Form 10-K ("2007 10-K").

The accompanying unaudited consolidated interim financial statements have been prepared in accordance with U.S. GAAP and reflect all adjustments that are, in the opinion of management, necessary for the fair presentation of the financial position and results of operations for the periods presented. All such adjustments are of a normal recurring nature. The results of operations for the quarter ended March 31, 2008 are not necessarily indicative of the results that may be expected for the year ending December 31, 2008.

Fair Value Measurements: Effective January 1, 2008, the Company adopted FASB Statement No. 157, Fair Value Measurements ("SFAS No. 157"), which, upon adoption, replaced various definitions of fair value in existing accounting literature with a single definition, established a framework for measuring fair value, and required additional disclosures about fair value measurements. SFAS No. 157 applies whenever an entity is measuring fair value under other accounting standards that require or permit fair value measurement. Although SFAS No. 157 is effective for financial statements issued for fiscal years beginning after November 15, 2007, the FASB provided a one-year deferral for implementation for non-financial assets and liabilities. The adoption of SFAS No. 157 on January 1, 2008 did not have a material impact on the Company's financial position, results of operations, or liquidity. Refer to Note 9, "Fair Value," for the Company's fair value measurement disclosures.

Fair Value Option: Effective January 1, 2008, the Company adopted Financial Accounting Standards Board ("FASB") Statement No. 159, The Fair Value Option for Financial Assets and Liabilities ("SFAS No. 159"). SFAS No. 159 permits entities to choose to measure certain financial assets and liabilities at fair value that are not currently required to be measured at fair value. The fair value option is applied on an instrument-by-instrument basis, is irrevocable and can only be applied to an entire instrument and not to specified risks, specified cash flows, or portions of that instrument. Changes in fair value (i.e. unrealized gains and losses) on items for which the fair value option has been elected will be reported in earnings at each subsequent reporting date and upfront fees and costs related to those items will be recognized in earnings as incurred and not deferred. SFAS No. 159 also requires entities to provide additional information that would help users of the financial statements understand how changes in fair values affect current-period earnings. While the Company did not elect the fair value option on the adoption date, it may elect this guidance for financial assets and liabilities in the future as permitted under the statement. Accordingly, the adoption of SFAS No. 159 on January 1, 2008 did not have an impact on the Company's financial position, results of operations, or liquidity.

Endorsement Split-Dollar Life Insurance Arrangements: Effective January 1, 2008, the Company adopted Emerging Issues Task Force ("EITF") Issue 06-4, Accounting for Deferred Compensation and Postretirement Benefit Aspects of Endorsement Split-Dollar Life Insurance Arrangements ("EITF 06-4"). The EITF is limited to the recognition of a liability and related compensation costs for endorsement split-dollar life insurance arrangements that provide a benefit to an employee that extends to postretirement periods. The effect of initially applying the guidance would be accounted for as a cumulative-effect adjustment to beginning retained earnings with the option of retrospective application. As the Company had already followed the provisions of this statement, the adoption of EITF 06-4 on January 1, 2008 did not have an impact on the Company's financial position, results of operations, or liquidity.

8

include: the acquisition date will be the date the acquirer obtains control; all (and only) identifiable assets acquired, liabilities assumed, and noncontrolling interests in the acquiree will be stated at fair value on the acquisition date; assets or liabilities arising from noncontractual contingencies will be measured at their acquisition date fair value only if it is more likely than not that they meet the definition of an asset or liability on the acquisition date; adjustments subsequently made to the provisional amounts recorded on the acquisition date will be made retroactively during a measurement period not to exceed one year; acquisition-related restructuring costs that do not meet the criteria in SFAS No.146, Accounting for Costs Associated with Exit or Disposal Activities, will be expensed as incurred; transaction costs will be expensed as incurred, except for debt or equity issuance costs which will be accounted for in accordance with other generally accepted accounting principles; reversals of deferred income tax valuation allowances and income tax contingencies will be recognized in earnings subsequent to the measurement period; and the allowance for loan losses of an acquiree will not be permitted to be recognized by the acquirer. Additionally, SFAS No. 141(R) will require new and modified disclosures surrounding subsequent changes to acquisition-related contingencies, contingent consideration, noncontrolling interests, acquisition-related transaction costs, fair values and cash flows not expected to be collected for acquired loans, and an enhanced goodwill rollforward. The Company will be required to prospectively apply SFAS No. 141(R) to all business combinations completed on or after January 1, 2009. Early adoption of SFAS No, 141(R) is not permitted, accordingly the Company will be required to record and disclose any business combinations in accordance with existing GAAP until January 1, 2009. The effect of these new requirements on the Company's financial position and results of operations will depend on the volume and terms of acquisitions in 2009 and beyond, but will likely increase the amount and change the timing of recognizing expenses related to acquisition activities.

Derivative Disclosures: In March 2008, the FASB issued SFAS No. 161, Disclosures about Derivative Instruments and Hedging Activities - an amendment of SFAS No. 133 ("SFAS No. 161"), which requires an entity to provide greater transparency about how its derivative and hedging activities affect its financial statements. SFAS No. 161 requires enhanced disclosures about (a) how and why an entity uses derivative instruments, (b) how derivative instruments and related hedged items are accounted for under SFAS No. 133, and (c) how derivative instruments and related hedged items affect an entity's financial position, results of operations and cash flows. SFAS No. 161 is effective for financial statements issued for fiscal years and interim periods beginning after November 15, 2008, with early application encouraged. Since SFAS No. 161 affects only disclosures, it will not impact the Company's financial position or results of operation upon adoption.