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                                                                     EXHIBIT 8.1

                       [SCHIFF HARDIN & WAITE LETTERHEAD]

                                 July 27, 2001

CIB Marine Bancshares, Inc.
N27 W24025 Paul Court
Pewaukee, Wisconsin 53072

     RE:FEDERAL INCOME TAX CONSEQUENCES OF A MERGER OF A NEWLY FORMED
        WHOLLY-OWNED SUBSIDIARY OF CIB MARINE BANCSHARES, INC. WITH AND INTO
        CITRUS FINANCIAL SERVICES, INC.

Gentlemen:

     You have requested our opinion related to the federal income tax
consequences to CIB Marine Bancshares, Inc., a Wisconsin corporation ("CIBM"),
Citrus Financial Services, Inc., a Florida corporation ("CFSI"), and CIBM
Acquisition Corporation, a Florida corporation and a wholly-owned subsidiary of
CIBM ("CIBMAC") arising out of the Agreement and Plan of Reorganization, dated
as of March 6, 2001, by and among CIBM, CFSI, and Citrus Bank, N.A., a national
banking association (the "Reorganization Agreement"), and the Plan of Merger by
and among CFSI and CIBMAC, dated March 6, 2001 ("Plan of Merger"). Our
conclusions are based upon (i) the facts and assumptions set forth below and
(ii) the written representations made by CIBM to us as of this date (the "CIBM
Letter"). Capitalized terms used but not defined in this letter have the meaning
given them in the Reorganization Agreement and the Plan of Merger.

     Our opinion does not address the tax consequences of the Merger (as defined
below) under state, local or foreign law.

                                     FACTS

     Pursuant to the Reorganization Agreement and the Plan of Merger, CIBMAC
shall be merged with and into CFSI in accordance with the applicable provisions
of the laws of the State of Florida (the "Merger"). CFSI shall be the surviving
corporation in the Merger and shall continue its corporate existence under the
laws of the State of Florida. As a result of the Merger, CIBMAC shall cease to
exist and CFSI shall become a direct wholly-owned subsidiary of CIBM.

     In the Merger (i) shares of CFSI Common Stock will be converted into the
right to receive a whole number of shares of CIBM Common Stock; and (ii) each
share of CIBMAC Common Stock will be converted into one fully paid and
nonassessable share of common stock of CFSI. Shareholders of CFSI will receive
cash in lieu of fractional interests in shares of CIBM Common Stock incident to
the Merger.

                                  ASSUMPTIONS

     In connection with this opinion, we have examined and are familiar with
originals or copies, certified or otherwise identified to our satisfaction, of
the Reorganization Agreement and the Plan of Merger, the CIBM Letter, and such
other documents as we have deemed necessary or appropriate as a basis for the
opinion set forth herein (together, the "Transaction Documents"). In addition,
we have assumed with your consent that (i) the Merger will be consummated in
accordance with the provisions of the Reorganization Agreement and the Plan of
Merger; (ii) the statements concerning the transaction set forth in the
Transaction Documents are true, correct and complete and will continue to be
true, correct and complete
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CIB Marine Bancshares, Inc.

July 27, 2001

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at all times; (iii) the representations made to us in the CIBM Letter are true,
correct and complete; and (iv) any representations made in the Reorganization
Agreement that are "to the best knowledge of" or similarly qualified are
correct, in each case without such qualification.

     In our examination, we have assumed the legal capacity of all natural
persons, the genuineness of all signatures, the completeness and authenticity of
all documents submitted to us as originals, the conformity to original documents
of all documents submitted to us as certified or photostatic copies and the
completeness and authenticity of the originals of such latter documents. In
making our examination of documents executed by parties, we have assumed that
such parties had the power and authority to enter into and perform their
obligations thereunder and have also assumed the due authorization, execution
and delivery by such parties of such documents. We have not independently
investigated or verified any of the foregoing.

                                    OPINION

     The opinions contained in this letter are only expressions of professional
judgment regarding the legal matters addressed and are not guarantees that a
court would reach any particular result.

     Based on the facts and assumptions set forth above and our examination and
review of the Proxy Statement/Prospectus included in the Registration Statement
on Form S-4 of which this opinion forms a part, and the accompanying exhibits
(the "Registration Statement") and the Transaction Documents referred to above,
we are of the opinion that:

     (1) The Merger will qualify as a reorganization within the meaning of
Section 368(a)(1)(A) of the Internal Revenue Code of 1986, as amended (the
"Code"), and each of CIBM, CFSI and CIBMAC will be "parties" to a reorganization
within the meaning of Section 368(b) of the Code.

     (2) No gain or loss will be recognized by CIBM, CFSI or CIBMAC in
connection with the Merger.

                                SCOPE OF OPINION

     Our opinion is based on present law and existing interpretations thereof by
the courts and the Internal Revenue Service. Any change in the facts, currently
or in the future, or any change in the law or existing interpretations thereof,
may adversely affect our opinion. Further, our opinion is not binding on the
Internal Revenue Service and the tax effects discussed above are not subject to
absolute resolution prior to the running of the statute of limitations or the
rendering of a final determination by a court of law or by closing agreement
with the Internal Revenue Service. Finally, it should be noted that we have
expressed no opinion except as specifically set forth herein.

                                    CONSENTS

     We hereby consent to the filing of this opinion with the Securities and
Exchange Commission as an exhibit to the Registration Statement and to the
reference to our firm under the heading "Federal Income Tax Consequences" and
"Legal Matters" in the Proxy Statement/Prospectus that constitutes part of the
Registration Statement.

                                          SCHIFF HARDIN & WAITE


                                          By:     /s/ THOMAS R. WECHTER
                                            ------------------------------------
                                                     Thomas R. Wechter