SECURITIES AND EXCHANGE COMMISSION
                             Washington D.C.  20549

                                  SCHEDULE 13D
                               (Amendment No. 6)

                   Under the Securities Exchange Act of 1934

                            BLACKHAWK BANCORP, INC.
                            a Wisconsin corporation
                                (Name of Issuer)

                     Common Stock, $.01 Par Value Per Share
                         (Title of Class of Securities)

                                  09237E 10 5
                                 (CUSIP Number)

                              Mr. Mark E. Robinson
                   Roethe, Krohn, Pope, McCarthy & Haas, LLP
                               305 S. Main Street
                              Janesville, WI 53545
                                 (608) 756-9710
          (Name, Address and Telephone Number of Person Authorized to
                      Receive Notices and Communications)

                               December 15, 2003
            (Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report
the acquisition which is the subject of this Schedule 13D, and is filing this
schedule because of Rule 13d-1(b) (3) or (4), check the following box [  ]

                         SCHEDULE 13D

1.   Name of Reporting Person
     S.S. or I.R.S. Identification No. of Above Person
     Kenneth A. Hendricks and Diane M. Hendricks

2.   Check the Appropriate Box if a Member of a Group
     (a)  [  ]      (b)  [  ]

3.   SEC Use Only

4.   Source of funds
          PF

5.   Check Box if Disclosure of Legal Proceedings is Required Pursuant to Items
     2(d) or 2(e)
                                   [  ]

6.   Citizenship or Place of Organization
          Wisconsin

     Number of Shares Beneficially Owned by Each Reporting Person With:

7.   Sole Voting Power
          8,100

8.   Shared Voting Power
          310,534

9.   Sole Dispositive Power
          8,100

10.  Shared Dispositive Power
          310,534

11.  Aggregate Amount Beneficially Owned by Each Reporting Person
          318,634

12.  Check Box if the Aggregate Amount in Row (11) Excluded Certain Shares
          [  ]

13.  Percent of Class Represented by Amount in Row (11)
          12.59%

14.  Type of Reporting Person
          IN

ITEM 1.   SECURITY AND ISSUER.

Name of Issuer and Address of Principal Executive Offices:

     Blackhawk Bancorp, Inc.
     400 Broad Street
     Beloit, Wisconsin 53511

Security to Which This Statement Relates:

     Common Stock, $.01 Par Value, per share ("Blackhawk Common Stock")

ITEM 2.   IDENTITY AND BACKGROUND.

    (a)-(c)  and (f).  This Schedule  13D is  filed on  behalf of  Mr. and  Mrs.
Kenneth A. Hendricks, individuals residing in  Wisconsin, who are both  citizens
of the United States of America.  Mr. Hendricks is Chairman and Chief  Executive
Officer of ABC Supply Co., a roofing and siding wholesaler. Mrs. Hendricks is  a
Vice President of ABC Supply Co. Mr. Hendricks  also is and has been a  Director
of Blackhawk Bancorp,  Inc. ("Blackhawk") since  1996. Mr. Hendricks'  principal
business office is located at One ABC Parkway, Beloit, Wisconsin 53511.

     (d) and (e). During the last five years, neither Mr. Hendricks nor Mrs.
Hendricks has (i) been convicted in a criminal proceeding (excluding traffic
violations or similar misdemeanors) or (ii) been a party to a civil proceeding
of a judicial or administrative body of competent jurisdiction and as a result
of such proceeding was or is subject to a judgment, decree or final order
enjoining future violations of, or prohibiting or mandating activities subject
to, federal or state securities laws or finding any violation with respect to
such laws.

ITEM 3.   SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

    Shares  of Blackhawk  Common Stock  owned  by Mr.  and Mrs.  Hendricks  were
acquired by them in Blackhawk's initial  public offering in 1990, or have  since
been acquired in secondary market and private transactions or are exercisable by
Mr. Hendricks  through  vesting  options granted  to  him  under  the  Blackhawk
Bancorp, Inc. 1994 Director Stock Option  Plan. Mr. and Mrs. Hendricks paid  the
purchase price or exercise  price, as the  case may be,  in connection with  his
acquisitions of all shares  of Blackhawk Common stock  with personal funds.  See
Item 5 below. Mr.  and Mrs. Hendricks purchased  the shares of Blackhawk  Common
Stock presently owned by them at  prices ranging from $3.33 to $10.50  (adjusted
to give effect  to Blackhawk's  1994 2-for-1 stock  split and  its 1995  3-for-2
stock split), and options presently owned by Mr. Hendricks which are exercisable
or which will become  exercisable within 60  days from the  date of this  filing
have exercise prices ranging from $8.50 to $15.00 a share.

ITEM 4.   PURPOSE OF THE TRANSACTION.

     On December 15,  2003, Mr.  and Mrs.  Hendricks acquired  36,200 shares  of
Blackhawk common  stock  on  a  private  transaction.    As  a  result  of  that
transaction, Mr. Hendricks beneficial ownership (as that term is defined in rule
13D-3 under the Securities Exchange Act of 1934 as amended) increased more  that
1 percentage point over the percentage  of Blackhawk's outsatnding common  stock
reported as beneficially by  Mr. and Mrs. Hendricks  when they previously  filed
Amendment No. 5  to this Schedule  D.   As of December  15, 2003,  Mr. and  Mrs.
Hendricks jointly  owned  310,534  shares of  Blackhawk  Common  Stock  and  Mr.
Hendricks held currently exercisable option(s) or options exercisable within  60
days of that date for  the purchase of an  additional 8,100 shares of  Blackhawk
Common Stock, resulting in  his beneficial ownership  of Blackhawk Common  Stock
totaling 318,634 shares or 12.59% of Blackhawk Common Stock (calculated pursuant
to Section 13(D)  of the Securities  Exchange Act of  1934 as  amended, and  the
Rules of Securities and Exchange Commission thereunder).   In addition, Mr.  and
Mrs. Hendricks,  consistent  with  the  Bank  Control  Act,  of  1978,  filed  a
notification with the Federal Reserve Bank, requesting authorization to  acquire
in excess of 10% of the  outstanding shares of Blackhawk  Bancorp.  On July  26,
2002, The Federal  Reserve Bank  of Chicago,  approved the  Hendricks intent  to
acquire control of Blackhawk Bancorp, consistent with notification as filed with
the Federal  Reserve.   As the  intent to  acquire control,  has been  approved,
without further  qualification  until  the Hendricks  exceed  15%  ownership  of
Blackhawk Bancorp, no further notification to the Federal Reserve is required at
this time.  Given  the current market  price of Blackhawk  Common Stock, or  any
exercisable price of exercisable  options held by  Mr. Hendricks, Mr.  Hendricks
presently has  no intention  to exercise  any of  his options  in the  immediate
future.

     As  specifically,  except  as   described  in  the  immediately   preceding
paragraph, Mr. and Mrs. Hendricks  had no plan or  proposal which relates to  or
which would result in:

          (a)  Other than through secondary market and/or private transactions
               as described above and the possible future exercise of options
               granted to him under Blackhawk's 1994 Directors' Stock Option
               Plan, the acquisition by any person of additional securities of
               Blackhawk, or the disposition of securities of Blackhawk;

          (b)  An extraordinary corporate transaction, such as a merger,
               reorganization or liquidation, involving Blackhawk or any of its
               subsidiaries;

          (c)  The sale or transfer of a material amount of assets of Blackhawk
               or  any of its subsidiaries;

          (d)  Any change in the present Board of Directors or management of
               Blackhawk, including any plans or proposals to change the number
               or terms of Directors or to fill any existing vacancies on the
               Board.

          (e)  Any material change in the present capitalization or dividend
               policy of Blackhawk;

          (f)  Any other material change in Blackhawk's business or corporate
               structure;

          (g)  Changes in Blackhawk's Articles of Incorporation, Bylaws or other
               actions which may impede the acquisition or control of Blackhawk
               by any person;

          (h)  Causing a class of securities of Blackhawk to be delisted from a
               national securities exchange or to cease to be authorized to be
               quoted in an interdealer quotation system of a registered
               national securities association;

          (i)  A class of equity securities of Blackhawk becoming eligible for
               termination of registration pursuant to Section 12(g)(4) of the
               Exchange Act; or

          (j)  Any Action similar to any of those enumerated above.

ITEM 5.   INTEREST IN SECURITIES OF THE ISSUER.

          (a) and (b) Mr. Hendricks presently owns jointly with his spouse
310,534 shares of Blackhawk Common Stock and holds presently exercisable options
(or options which will become exercisable within 60 days after December 15,
2003) for the purchase of up to an additional 8,100 shares of Blackhawk Common
Stock.

          (c) During the past 60 days, Mr. and Mrs. Hendricks have acquired the
following shares of stock in private transactions:

                                          Number of
     Owner             Date               Interests  Purchase Price  Total Paid
     -----             ----               ---------  --------------  ----------
Mr. & Mrs. Hendricks   December 15, 2003   36,200        $12.00       $434,400

          (d)   As noted above, all of Mr. Hendricks' shares of Blackhawk Common
Stock are owned jointly with his spouse.

          (e)   Not Applicable.

ITEM 6.   CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH
          RESPECT TO SECURITIES OF THE ISSUER.

     Other than Blackhawk's 1994 Directors' Stock Option Plan, which is
incorporated by reference in this Schedule 13D, and agreements referred to or
contained therein, there are no contracts, arrangements, understanding or
relationships between Mr. Hendricks and any other person, or with respect to any
securities of Blackhawk.

ITEM 7.   MATERIAL TO BE FILED AS EXHIBITS.

     Mr. Hendricks hereby incorporates into this Schedule 13D the following
exhibits by reference to the filings set forth Below:

                               EXHIBIT INDEX
Exhibit No.
-----------

     1.       The Blackhawk Bancorp, Inc. 1994 Directors' Stock Option Plan is
incorporated as filed previously by reference to Exhibit 28.4 to Blackhawk's
Registration Statement on Form S-8 (Reg. No. 33-90550).

                               SIGNATURE

     After reasonable inquiry and to the best of our knowledge and belief, we
certify that the information set forth in this statement is true, complete and
correct.

     Date: December 15, 2003.

                                        /s/ Kenneth A. Hendricks
                                        ------------------------
                                        Kenneth A. Hendricks

                                        /s/ Diane M. Hendricks
                                        ------------------------
                                        Diane M. Hendricks