EXHIBIT 5.1

              BARACK FERRAZZANO KIRSCHBAUM PERLMAN & NAGELBERG LLC
                        333 WEST WACKER DRIVE, SUITE 2700
                             CHICAGO, ILLINOIS 60606
                            Telephone (312) 984-3100
                            Facsimile (312) 984-3150



                                 March 24, 2004



Heartland Financial USA, Inc.
1398 Central, P.O. Box 778
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 acquisition by
merger of Rocky Mountain Bancorporation, Inc., a Montana corporation ("RMB"), as
described in the Form S-4 Registration Statement to be filed by the Company with
the Securities and Exchange Commission (the "SEC") under the Securities Act of
1933, as amended (together with all amendments thereto, the "Registration
Statement"). As described in the Registration Statement, RMB Acquisition
Corporation, a Montana corporation and a wholly-owned subsidiary of the Company
("Acquisition Sub"), will merge with and into RMB, with RMB surviving (such
merger, the "Initial Merger") and, immediately thereafter, RMB will merge with
and into the Company, with the Company surviving (such merger, together with the
Initial Merger, the "Mergers"). You have requested our opinion concerning
certain matters in connection with the Registration Statement.

         We have made such legal and factual investigation as we deemed
necessary for purposes of this opinion. In our investigation, we have assumed
the genuineness of all signatures, the proper execution of all documents
submitted to us as originals, the conformity to the original documents of all
documents submitted to us as copies and the authenticity of the originals of
such copies.

         In arriving at the opinions expressed below, we have reviewed and
examined the following documents:

         (a)      the Certificate of Incorporation and Bylaws of the Company;

         (b)      the Agreement and Plan of Merger by and among the Company, RMB
                  and Acquisition Sub, dated as of February 6, 2004 (the "Merger
                  Agreement");

         (c)      the Registration Statement, including the proxy
                  statement-prospectus constituting a part thereof (the "Proxy
                  Statement-Prospectus"); and

         (d)      resolutions of the Board of Directors of the Company relating
                  to the merger transaction.




BARACK FERRAZZANO KIRSCHBAUM PERLMAN & NAGELBERG

Heartland Financial USA, Inc.
March 24, 2004
Page 2


         We call your attention to the fact that we are qualified to practice
law in the State of Illinois and express no opinion concerning any law other
than the General Corporation Law of the State of Delaware and the laws of the
United States of America.

         Based upon the foregoing, but assuming no responsibility for the
accuracy or the completeness of the data supplied by the Company and subject to
the qualifications, assumptions and limitations set forth herein, it is our
opinion that:

         (1)      The shares of the Company's common stock, $0.01 par value per
                  share, to be issued to the stockholders of RMB as a result of
                  the Initial Merger, when issued by the Company pursuant to the
                  Merger Agreement, in connection with the Initial Merger, will
                  be legally issued, fully paid and non-assessable shares of the
                  Company; provided that the Initial Merger has been consummated
                  in accordance with the terms and conditions contained in the
                  Merger Agreement.

         (2)      Provided that the Mergers have been consummated in accordance
                  with the terms and conditions contained in the Merger
                  Agreement, the Mergers will qualify as mergers under the laws
                  of the States of Delaware and Montana.

         We express no opinion with respect to any specific legal issues other
than those explicitly addressed herein. We assume no obligation to advise you of
any change in the foregoing subsequent to the date of this opinion (even though
the change may affect the legal conclusion stated in this opinion letter).

         We hereby consent to the use in the Proxy Statement-Prospectus of our
name, the statements with respect to us as appearing under the heading "Certain
Opinions" in the Proxy Statement-Prospectus and to the use of this opinion as an
exhibit to the Registration Statement.


                                   Very truly yours,

                                   /s/ Barack Ferrazzano Kirschbaum Perlman &
                                   Nagelberg LLC

                                   BARACK FERRAZZANO KIRSCHBAUM
                                   PERLMAN & NAGELBERG LLC