Exhibit 5.1

Barack Ferrazzano Kirschbaum Perlman & Nagelberg LLP

333 WEST WACKER DRIVE, SUITE 2700

CHICAGO, ILLINOIS 60606

Telephone (312) 984-3100

Facsimile (312) 984-3150

May 17, 2005

Heartland Financial USA, Inc.

1398 Central Street

Dubuque, Iowa 52004-0778

Ladies and Gentlemen:

We have acted as special counsel to Heartland Financial USA, Inc., a Delaware corporation (the “Company”), in connection with the proposed offering of up to (i) 1,000,000 shares of its common stock, $1.00 par value (“Common Shares”), pursuant to the Company’s 2005 Long-Term Incentive Plan and (ii) 500,000 Common Shares pursuant to the Company’s 2006 Employee Stock Purchase Plan (together, with the Company’s 2005 Long-Term Incentive Plan, the “Plans”), each as described in the Form S-8 Registration Statement (the “Registration Statement”) to be filed with the Securities and Exchange Commission (the “SEC”). In so acting, we have examined and relied upon the originals, or copies certified or otherwise identified to our satisfaction, of such records, documents and other instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. Capitalized terms used, but not defined, herein shall have the meanings given such terms in the Registration Statement.

Based on the foregoing, we are of the opinion that the Common Shares have been duly authorized and, when the Registration Statement becomes effective and the Common Shares have been issued in accordance with the Plans, the Common Shares will be validly issued, fully paid and nonassessable. With respect to the opinions expressed above, we are qualified to practice law in the State of Illinois and express no opinion concerning any law other than the laws of the State of Illinois, the General Corporation Law of the State of Delaware and the laws of the United States of America.

This opinion is being furnished to you solely for your benefit in connection with the transactions set forth above. It may not be relied upon by, nor a copy of it delivered to any other party, without our prior written consent. This opinion is based upon our knowledge of the law and facts as of the date hereof, and we assume no duty to communicate with you with respect to any matter that comes to our attention hereafter.

We consent to the filing of this opinion with the Securities and Exchange Commission as an exhibit to the Registration Statement. In giving the foregoing consents, we do not thereby admit that we come within the category of persons whose consent is required under Section 7 of the Act, or the rules and regulations of the Commission promulgated thereunder.

Sincerely,
        /s/ Barack Ferrazzano Kirschbaum

Perlman & Nagelberg LLP

BARACK FERRAZZANO KIRSCHBAUM PERLMAN & NAGELBERG LLP