--------                                        -----------------------------
 FORM 4                                                  OMB APPROVAL
--------                                        -----------------------------
----- Check this box if no longer               OMB Number:       3235-0287
      subject to Section 16. Form 4             Expires: January 31, 2005
----- or Form 5 obligations may                 Estimated average burden
      continue. SEE Instruction 1(b).           hours per response .... 0.5
                                                -----------------------------

              UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                       WASHINGTON, D.C. 20549

                 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

     Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934,
      Section 17(a) of the Public Utility Holding Company Act of 1935 or
             Section 30(f) of the Investment Company Act of 1940

(Print or Type Responses)

- ---------------------------------------------------------------------------
1. Name and Address of Reporting Person*

   Ardsley Advisory Partners
- ---------------------------------------------------
   (Last)          (First)              (Middle)

   262 Harbor Drive
- ----------------------------------------------------
                   (Street)

   Stamford           CT                  06902
- ----------------------------------------------------
   (City)           (State)               (Zip)

- ---------------------------------------------------------------------------
2. Issuer Name and Ticker or Trading Symbol

    OM Group, Inc. (OMG)
- ---------------------------------------------------------------------------
3. IRS or Social Security Number of Reporting Person (Voluntary)

- ---------------------------------------------------------------------------

4. Statement for Month/Day/Year

   12/05/02
- ---------------------------------------------------------------------------
5. If Amendment, Date of Original (Month/Day/Year)

- ---------------------------------------------------------------------------


                                                                  Page 1 of 6





6. Relationship of Reporting Person(s) to Issuer (Check all applicable)

   [ ] Director
   [X] 10% Owner
   [ ] Officer (give title below)
   [ ] Other (specify below)

- ---------------------------------------------------------------------------
7. Individual or Joint/Group Filing (Check Applicable Line)

   [ ] Form filed by One Reporting Person
   [X] Form filed by More than One Reporting Person
- ---------------------------------------------------------------------------

TABLE I--NON-DERIVATIVE SECURITIES ACQUIRED, DISPOSED OF, OR BENEFICIALLY
OWNED
----------------------------------------------------------------------------
1. Title of    2. Trans-  2A. Deemed    3. Trans-    4. Securities Acquired
   Security       action      Execution    action       (A) or Disposed of (D)
   (Instr. 3)     Date        Date, if     Code         (Instr. 3, 4 and 5)
                  (Month/     any (Month/  (Instr. 8)    ----------------------
                  Day/        Day/         ----------    Amount  (A) or  Price
                  Year)       Year)         Code   V             (D)


----------------------------------------------------------------------------
                                                       
----------------------------------------------------------------------------
----------------------------------------------------------------------------
OM Group Inc., Common Stock,
$0.01 par value
per share
("Common Stock")  12/05/02                  P            25,000  A     $7.724
----------------------------------------------------------------------------

----------------------------------------------------------------------------


                                                                  Page 2 of 6


5. Amount of     6. Ownership        7. Nature of
   Securities       Form: Direct        Indirect
   Beneficially     (D) or Indirect     Beneficial
   Owned following  (I) (Instr. 4)      Ownership
   Reported                             (Instr. 4)
   Transactions
  (Instr. 3
    and 4)
----------------------------------------------------------------------------
   2,875,000            I(1)(2)                (1)(2)
----------------------------------------------------------------------------






Reminder: Report on a separate line for each class of securities
beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, SEE
Instruction 4(b)(v).



TABLE II - DERIVATIVE SECURITIES ACQUIRED, DISPOSED OF, OR BENEFICIALLY OWNED
           (E.G., PUTS, CALLS, WARRANTS, OPTIONS, CONVERTIBLE SECURITIES)
----------------------------------------------------------------------------
1. Title of Derivative 2. Conver- 3. Transac- 4. Transac-  5. Number of
   Security (Instr. 3)    sion or    tion Date   tion Code    Derivative
                          Exercise   (Month/     (Instr. 8)   Securities
                          Price of    Day/     ------------   Acquired (A)
                          Deriv-      Year)      Code  V      or Disposed
                          ative                               of (D) (Instr.
                          Security                            3, 4, and 5)
                                                              -------------
                                                               (A)      (D)
----------------------------------------------------------------------------
                                                  
----------------------------------------------------------------------------

----------------------------------------------------------------------------
6. Date Exer-       7. Title and Amount  8. Price of
   cisable and         of Underlying        Derivative
   Expiration Date     Securities           Security
   (Month/Day/         (Instr. 3 and 4)     (Instr. 5)
   Year)               -------------------
-----------------            Amount or
Date     Expira-      Title  Number of
Exer-    tion                Shares
cisable  Date
----------------------------------------------------------------------------
                                   
----------------------------------------------------------------------------

                                                                  Page 3 of 6





----------------------------------------------------------------------------
9. Number of     10. Ownership     11. Nature of
   Derivative        Form of           Indirect
   Securities        Derivative        Beneficial
   Beneficially      Security:         Ownership
   Owned at          Direct (D) or     (Instr. 4)
   End of Month      Indirect (I)
   (Instr. 4)        (Instr. 4)
----------------------------------------------------------------------------
                                     
----------------------------------------------------------------------------
----------------------------------------------------------------------------

----------------------------------------------------------------------------



Explanation of Responses

(1)  The shares of Common Stock to which this note relates are held  directly by
     Ardsley Offshore Fund Ltd., a British Virgin Islands corporation  ("Ardsley
     Offshore"),  as to 800,000  shares;  Ardsley    Partners   Fund II, L.P., a
     Delaware limited  partnership   ("Ardsley   Fund  II"),   as  to    725,000
     shares;  Ardsley Partners Fund I, L.P.,   a   Delaware limited  partnership
     ("Ardsley Fund I"), as to 425,000  shares;  Ardsley Partners  Institutional
     Fund, L.P., a Delaware  limited   partnership,  ("Ardsley  Institutional"),
     as to 450,000  shares;    and   Augusta   Partners L.P. a Delaware  limited
     partnership  ("Augusta"),  as to 475,000 shares.

(2)  Ardsley  Advisory  Partners  serves  as  investment  manager  to,  and  has
     investment discretion over the securities held by Ardsley Offshore. Ardsley
     Advisory Partners also serves a non-managing  member of Augusta  Management
     L.L.C.,  the investment  advisor to Augusta and has  investment  discretion
     over the  securities  held by  Augusta.  Ardsley  Partners  I serves as the
     general partner of, and has investment  discretion over the securities held
     by Ardsley  Fund II,  Ardsley  Fund I and  Ardsley  Institutional.  Ardsley
     Partners I also serves as the general partner of Ardsley Advisory Partners.
     Philip J. Hempelman,  is the managing partner of Ardsley Advisory  Partners
     and the general partner of Ardsley Partners I. Ardsley Advisory   Partners,
     Ardsley Partners I and Philip J. Hempelman  each  disclaim  any  beneficial
     ownership of any of the Issuer's  securities  to which  this Form 4 relates
     for the  purposes  of Section 16 of the Securities Exchange Act of 1934, as
     amended, except as to such  securities  representing  in  which  each  such
     person may be deemed to have an indirect  pecuniary  interest  pursuant  to
     Rule 16a-1(a)(2).


                                                                  Page 4 of 6




* If the form is filed by more than one reporting person, SEE
Instruction 4(b)(v).

**Intentional misstatements or omissions of facts constitute Federal Criminal
Violations.  SEE 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this form, one of which must be manually signed.
If space is insufficient, SEE Instruction 6 for procedure.

 Ardsley Advisory Partners

                      /s/ Philip J. Hempelman,            12/09/02
                    ---------------------------------     --------
                     Name: Philip J. Hempelman            Date
                     Title: Managing Partner
                     **Signature of Reporting Person

                                  Joint Filer Information

Name:  Ardsley Offshore Fund Ltd.
Address:   Romasaco Place, Wickhams Cay 1, Roadtown Tortola,
           British Virgin Islands
Designated Filer:  Ardsley Advisory Partners
Issuer & Ticker Symbol:  OM Group, Inc.(OMG)
Date of Event Requiring Statement:   12/05/02

Signature: Ardsley Offshore Fund, Ltd.

                  By: Neil Glass, its Vice President and Administrative Manager
                  By:   /s/ Neil Glass
                  -----------------------------------------------------------
                  Name: Neil Glass
                  Title: Vice President and Administrative Manager


Name:  Ardsley Partners Fund II, L.P.
Address:   262 Harbor Drive, Stamford, Connecticut 06902
Designated Filer:  Ardsley Advisory Partners
Issuer & Ticker Symbol:  OM Group, Inc.(OMG)
Date of Event Requiring Statement:   12/05/02

Signature: Ardsley Partners Fund II, L.P.

                  By: Ardsley Partners I, its general partner
                  By:   /s/ Philip J. Hempelman
                  -----------------------------------------------------------
                  Name: Philip J. Hempelman
                  Title: General Partner


Name:  Ardsley Partners Fund I, L.P.
Address:   262 Harbor Drive, Stamford, Connecticut 06902
Designated Filer:  Ardsley Advisory Partners
Issuer & Ticker Symbol:  OM Group, Inc.(OMG)
Date of Event Requiring Statement:   12/05/02

Signature: Ardsley Partners Fund I, L.P.

                  By: Ardsley Partners I, its general partner
                  By:   /s/ Philip J. Hempelman
                  -----------------------------------------------------------
                  Name: Philip J. Hempelman
                  Title: General Partner


                                                                  Page 5 of 6



Name: Ardsley Partners Institutional Fund, L.P.
Address:   262 Harbor Drive, Stamford, Connecticut 06902
Designated Filer:  Ardsley Advisory Partners
Issuer & Ticker Symbol:  OM Group, Inc.(OMG)
Date of Event Requiring Statement:   12/05/02

Signature: Ardsley Partners Institutional Fund, L.P.

                  By: Ardsley Partners I, its general partner
                  By:   /s/ Philip J. Hempelman
                  -----------------------------------------------------------
                  Name: Philip J. Hempelman
                  Title: General Partner


Name: Augusta Partners L.P.
Address:   622 Third Avenue, New York, New York 10017
Designated Filer:  Ardsley Advisory Partners
Issuer & Ticker Symbol:  OM Group, Inc.(OMG)
Date of Event Requiring Statement:   12/05/02

Signature: Augusta Partners L.P.

                  By: Howard Singer, its general partner
                  By:   /s/ Howard Singer
                  -----------------------------------------------------------
                  Name: Howard Singer
                  Title: General Partner


Name:  Ardsley Partners I
Address:   262 Harbor Drive, Stamford, Connecticut 06902
Designated Filer:  Ardsley Advisory Partners
Issuer & Ticker Symbol:  OM Group, Inc.(OMG)
Date of Event Requiring Statement:   12/05/02

Signature: Ardsley Partners I

                  By:   /s/ Philip J. Hempelman
                  -----------------------------------------------------------
                  Name: Philip J. Hempelman
                  Title: General Partner


Name: Philip J. Hempelman
Address:  c/o Ardsley Advisory Partners  262 Harbor Drive, Stamford,
          Connecticut 06902
Designated Filer:  Ardsley Advisory Partners
Issuer & Ticker Symbol:  OM Group, Inc.(OMG)
Date of Event Requiring Statement:   12/05/02

Signature:        /s/ Philip J. Hempelman
                  -----------------------------------------------------------
                  Name: Philip J. Hempelman



                                                            Page 6 of 6