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

   01/30/03
- ---------------------------------------------------------------------------
5. If Amendment, Date of Original (Month/Day/Year)

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


                                                                  Page 1 of 7


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")  01/30/03                  P         25,000     A    $8.8039
----------------------------------------------------------------------------


                                                                  Page 2 of 7




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)
----------------------------------------------------------------------------
   3,904,200            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 7



----------------------------------------------------------------------------
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 1,175,000 shares; Ardsley Partners Fund II,
      L.P.,  a  Delaware  limited  partnership  ("Ardsley  Fund  II"),  as to
      1,025,000 shares; Ardsley Partners Institutional Fund, L.P., a Delaware
      limited partnership,  ("Ardsley Institutional"),  as to 535,000 shares;
      Augusta Partners L.P. a Delaware limited partnership ("Augusta"), as to
      515,000 shares;  Philip J. Hempleman,  the managing  partner of Ardsley
      Advisory  Partners and the general partner of Ardsley  Partners I as to
      425,000  shares;  the Carter  Hempleman Trust ("Carter  Trust"),  as to
      52,000 shares;  the Spencer  Hempleman Trust ("Spencer  Trust"),  as to
      52,200  shares;  the Hempleman  Family Trust  ("Family  Trust"),  as to
      75,000 shares; and Marion Lynton ("Lynton") as to 50,000 shares.

(2)   Ardsley  Advisory  Partners  serves as  investment  manager to, and has
      investment  discretion over the securities held by Ardsley Offshore and
      the  Lynton  account.  Ardsley  Advisory  Partners  also  serves  as  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 and  Ardsley  Institutional.  Ardsley  Partners I also serves as the
      general partner of Ardsley Advisory  Partners.  Philip Hempleman serves
      as trustee to and has discretion over the securities held by the Carter
      Trust,  the  Spencer  Trust  and the  Family  Trust.  Ardsley  Advisory
      Partners and Ardsley Partners I 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 7




* 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. Hempleman            01/31/03
                                     -------------------------------    --------
                                     Name: Philip J. Hempleman          Date
                                     Title: Managing Partner

                            Joint Filer Information

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:   01/30/03

Signature: Ardsley Partners Fund II, L.P.

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

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:   01/30/03

Signature: Ardsley Partners Institutional Fund, L.P.

                  By: Ardsley Partners I, its general partner
                  By: /s/ Philip J. Hempleman
                  -----------------------------------------------------------
                  Name: Philip J. Hempleman
                  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:   01/30/03

Signature: Ardsley Partners I

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


                                                                  Page 5 of 7



Name: Philip J. Hempleman
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:   01/30/03

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

Name: Carter Hempleman Trust
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:   01/30/03

Signature:        Carter Hempleman Trust

                  BY: /s/ Philip J. Hempleman
                  -----------------------------------------------------------
                  Name: Philip J. Hempleman
                  Title: Trustee

Name: Spencer Hempleman Trust
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:   01/30/03

Signature:        Spencer Hempleman Trust

                  BY: /s/ Philip J. Hempleman
                  -----------------------------------------------------------
                  Name: Philip J. Hempleman
                  Title: Trustee

Name: Hempleman Family Trust
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:   01/30/03

Signature:        Hempleman Family Trust

                  BY: /s/ Philip J. Hempleman
                  -----------------------------------------------------------
                  Name: Philip J. Hempleman
                  Title: Trustee


                                                                   Page 6 of 7



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:   01/30/03

Signature:        Augusta Partners L.P.

                  By:  /s/ Howard Singer
                  -----------------------------------------------------------
                  Name: Howard Singer
                  Title: General Partner

Name:  Ardsley Offshore Fund Ltd.
Address:  Romasaco Place, Wickhams Cay I, Roadtown Tortola,
          British Virgin Islands
Designated Filer:  Ardsley Advisory Partners
Issuer & Ticker Symbol:  OM Group, Inc.(OMG)
Date of Event Requiring Statement:   01/30/03

Signature:        Ardsley Offshore Fund, Ltd.

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

Name: Marion Lynton
Address:  961 Senimore Road, Larchmont, NY 10538
Designated Filer:  Ardsley Advisory Partners
Issuer & Ticker Symbol:  OM Group, Inc.(OMG)
Date of Event Requiring Statement:   01/30/03

Signature:         /s/ Marion Lynton
                  -----------------------------------------------------------
                  Name: Marion Lynton














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