As filed with the Securities and Exchange Commission on September 30, 2004

                                                    Registration No. 333-_______

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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                               UNIONBANCORP, INC.
             (Exact name of registrant as specified in its charter)

                   DELAWARE                               36-3145350
       (State or other jurisdiction of                (I.R.S. employer
       incorporation or organization)                 identification no.)

                              321 West Main Street
                             Ottawa, Illinois 61350
          (Address of principal executive offices, including zip code)

                               UNIONBANCORP, INC.
                             2003 STOCK OPTION PLAN
                            (Full title of the plan)

                                          WITH A COPY TO:
DEWEY R. YAEGER                           TIMOTHY E. KRAEPEL
PRESIDENT AND CHIEF EXECUTIVE OFFICER     HOWARD & HOWARD ATTORNEYS, P.C.
UNIONBANCORP, INC.                        THE PINEHURST OFFICE CENTER, SUITE 101
321 WEST MAIN STREET                      39400 NORTH WOODWARD AVENUE
OTTAWA, ILLINOIS 61350                    BLOOMFIELD HILLS, MICHIGAN 48304-5151
(Name and address of agent for service)   (248) 645-1483
(815) 431-2720
(Telephone number, including area code, of agent for service)

                         CALCULATION OF REGISTRATION FEE
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                                                           Proposed         Proposed
                                             Amount         maximum          maximum
                                              to be     offering price      aggregate
                                           registered      per share     offering price       Amount of
Title of Securities to be Registered           (1)            (2)              (2)        Registration fee
-----------------------------------------------------------------------------------------------------------
                                                                              
   Common Stock, $1.00 par value             200,000        $20.715        $4,143,000          $525.00
===========================================================================================================


(1) Plus, pursuant to Rule 416, an indeterminate number of additional shares as
may be issuable in the event of an adjustment as a result of an increase in the
number of issued shares of Registrant's Common Stock resulting from a
subdivision of such shares, the payment of stock dividends or certain other
capital adjustments as provided in the above-referenced 2003 Stock Option Plan.

(2) Estimated solely for purposes of calculating the registration fee in
accordance with Rule 457(c) and (h) based on the $20.715 average of the high and
low prices of Registrant's Common Stock on The Nasdaq Stock Market on September
28, 2004.



                                     PART I.

ITEM 1.           PLAN INFORMATION*

ITEM 2.           REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION*

* Information required by Part I to be contained in this Section 10(a)
prospectus is omitted from the Registration Statement in accordance with Rule
428 under the Securities Act of 1933, as amended ("Securities Act"), and the
Note to Part I on Form S-8.

                                    PART II.

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.           INCORPORATION OF DOCUMENTS BY REFERENCE

      The following documents filed with the Securities and Exchange Commission
(the "Commission") by the Registrant (File No. 0-28846) are incorporated in this
Registration Statement by reference:

      (1)   the Registrant's Annual Report on Form 10-K for the year ended
December 31, 2003;

      (2)   the Registrant's Quarterly Report on Form 10-Q for the quarters
ended March 31, 2004 and June 30, 2004;

      (3)   all other reports filed by the Registrant pursuant to Section 13(a)
or 15(d) of the Securities Exchange Act of 1934 (the "Exchange Act") since
December 31, 2003;

      (4)   the information contained in the Registrant's definitive Proxy
Statement filed with the Commission on March 26, 2004 relating to its 2004
Annual Meeting of Stockholders (with the exception of the compensation committee
report, the audit committee report, and the performance graph which are not
incorporated by reference); and

      (5)   the description of Registrant's Common Stock, $1.00 par value which
is contained in Item 1 of Registrant's Registration Statement on Form 8-A (File
No. 0-28846) filed with the Commission on September 4, 1996, including any
amendments or reports filed for the purpose of updating such description.

      All documents filed by the Registrant pursuant to Sections 13(a), 13(c),
14 and 15(d) of the Exchange Act after the date of this Registration Statement
and prior to the filing of a post effective amendment which indicates that all
securities offered have been sold or which deregisters all securities then
remaining unsold shall be deemed to be incorporated by reference in this
Registration Statement and to be a part hereof from the date of filing such
documents.

                                        2



ITEM 4.           DESCRIPTION OF SECURITIES

         Not applicable.

ITEM 5.           INTERESTS OF NAMED EXPERTS AND COUNSEL

         Not applicable.

ITEM 6.           INDEMNIFICATION OF DIRECTORS AND OFFICERS

      Section 145 of the General Corporation Law of the State of Delaware
("Section 145"), Article VIII of the Registrant's Restated Certificate of
Incorporation, as amended, and Article VII of the Registrant's By-Laws provide
for the indemnification of the Registrant's directors and officers in a variety
of circumstances, which may include indemnification for liabilities under the
Securities Act of 1933. The general effect of these provisions is to provide
that the Registrant shall indemnify its directors and officers against expenses
(including attorneys' fees), judgments, fines and amounts paid in settlement
actually and reasonably incurred by them in the proceeding in which such persons
are made a party by reason of being or having been a director or officer of
Registrant, but only if it is determined that they acted in good faith and in a
manner they reasonably believed to be in or not opposed to the best interest of
the Registrant and, with respect to any criminal action or proceeding, had no
reasonable cause to believe their conduct was unlawful. Such determination may
be made by (i) a majority vote of a quorum consisting of disinterested
directors, (ii) an independent legal counsel in a written opinion (if no such
quorum is available or if a quorum of disinterested directors so directs), or
(iii) the stockholders. The Registrant will pay expenses incurred by its
directors and officers prior to the final disposition of such action, suit or
proceeding, if the director or officer undertakes to repay such amount unless it
is ultimately determined that they are entitled to be indemnified by the
Registrant.

      The Registrant has insurance which, subject to certain policy limits,
deductible amounts and exclusions, insures directors and officers of the
Registrant for liabilities incurred as a result of acts committed in their
capacity as directors and officers or claims made against them by reason of
their status as directors or officers.

      As permitted pursuant to Section 102(b)(7) of the General Corporation Law
of the State of Delaware, the Restated Certificate of Incorporation, as amended,
of the Registrant eliminates the personal monetary liability of a director of
the Registrant or its stockholders for breach of fiduciary duty as a director,
except for liability that results from (i) any breach of the director's duty of
loyalty to the Registrant or its stockholders; (ii) acts or omissions not in
good faith or which involve intentional misconduct or a knowing violation of
law, (iii) Section 174 of the General Corporation Law of the State of Delaware
(which Section pertains to a director's liability for unlawful payments of
dividends or unlawful stock purchases or redemptions); or (iv) any transaction
from which the director derived an improper personal benefit.

                                        3



ITEM 7.           EXEMPTION FROM REGISTRATION CLAIMED

         Not applicable.

ITEM 8.           EXHIBITS

      The exhibits filed herewith or incorporated by reference herein are set
forth in the Exhibit index filed as part of this Registration Statement on page
8 hereof.

ITEM 9.           UNDERTAKINGS

      The undersigned Registrant hereby undertakes:

      (1)   To file, during any period in which offers or sales are being made,
a post-effective amendment to this Registration Statement:

            (i)  To include any prospectus required by Section 10(a)(3) of the
      Securities Act of 1933;

            (ii) To reflect in the prospectus any facts or events arising after
      the effective date of the Registration Statement (or the most recent
      post-effective amendment thereof) which, individually or in the aggregate,
      represent a fundamental change in the information set forth in the
      Registration Statement;

            (iii) To include any material information with respect to the plan
      of distribution not previously disclosed in the Registration Statement or
      any material change to such information in the Registration Statement;

PROVIDED, HOWEVER, that paragraphs (1)(i) and (1)(ii) do not apply if the
Registration Statement is on Form S-3, Form S-8, and the information required to
be included in a post-effective amendment by those paragraphs is contained in
period reports filed by the Registrant pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934 that are incorporated by reference in the
Registration Statement.

      (2)   That, for the purpose of determining any liability under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial BONA
FIDE offering thereof.

      (3)   To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering.

            The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where

                                        4



applicable, each filing of an employee benefit plan's annual report pursuant to
section 15(d) of the Securities Exchange Act of 1934) that is incorporated by
reference in the Registration Statement shall be deemed to be a new registration
statement relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial BONA FIDE offering
thereof.

            Insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to directors, officers and controlling
persons of the Registrant pursuant to the foregoing provisions, or otherwise,
the Registrant has been advised that in the opinion of the Securities and
Exchange Commission such indemnification is against public policy as expressed
in the Act and is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
Registrant of expenses incurred or paid by a director, officer or controlling
person of the Registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the Registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Act and will
be governed by the final adjudication of such issue.

                                        5



                                   SIGNATURES

      The Registrant. Pursuant to the requirements of the Securities Act of
1933, the Registrant certifies that it has reasonable grounds to believe that it
meets all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Ottawa, State of Illinois, on September 30,
2004.

                      UNIONBANCORP, INC.
                          (Registrant)

                      By:      /s/Dewey R. Yaeger
                         -------------------------------------------------------
                               Dewey R. Yaeger
                               President, Chief Executive Officer and Director
                               (Principal Executive Officer)

                      By:      /s/Kurt R. Stevenson
                         -------------------------------------------------------
                               Kurt R. Stevenson
                               Senior Vice President and Chief Financial Officer
                               (Principal Financial Officer)

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.



                  Signature                                             Title                                Date
--------------------------------------------             ----------------------------------           -------------------
                                                                                                
     /s/Dewey R. Yaeger                                  President, Chief Executive Officer           September 30, 2004
--------------------------------------------             (Principal Executive Officer)
Dewey R. Yaeger                                          and Director

    **                                                   Chairman of the Board                        September 30, 2004
--------------------------------------------             and Director
Dennis J. McDonnell

    **                                                   Director                                     September 30, 2004
--------------------------------------------
Richard J. Berry

    **                                                   Director
--------------------------------------------
Walter E. Breipohl                                                                                    September 30, 2004


                                        6




                                                                                                
    **                                                   Director                                     September 30, 2004
--------------------------------------------
Robert J. Dotty

    **                                                   Director                                     September  30, 2004
--------------------------------------------
I.J. Reinhardt, Jr.

    **                                                   Director
--------------------------------------------
John A. Shinkle                                                                                       September  30, 2004

    **                                                   Director
--------------------------------------------
Scott C. Sullivan                                                                                     September  30, 2004

    **                                                   Director
--------------------------------------------
John A. Trainor                                                                                       September  30, 2004


**By:    /s/Dewey R. Yaeger
     ---------------------------------------
         Dewey R. Yaeger
         Attorney-in-Fact

                                        7



                                  EXHIBIT INDEX



EXHIBIT
NUMBER                         DESCRIPTION
-------     -------------------------------------------------
         
5.1         Opinion of Howard & Howard Attorneys, P.C.

23.1        Consent of Crowe, Chizek and Company, LLP

23.2        Consent of Howard & Howard Attorneys, P.C.
            (contained in their opinion filed as Exhibit 5.1).

24          Power of Attorney


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