BOSTON PARTNERS
                                 FAMILY OF FUNDS

                     BOSTON PARTNERS LONG/SHORT EQUITY FUND

                  (INVESTMENT PORTFOLIO OF THE RBB FUND, INC.)

                                 INVESTOR CLASS

    Supplement dated September 15, 2004 to Prospectus dated December 31, 2003
                         as supplemented April 26, 2004

         THE   SUB-PARAGRAPH   OF  THE  PROSPECTUS   ENTITLED  "BOSTON  PARTNERS
LONG/SHORT  EQUITY FUND" UNDER THE CAPTION  "PORTFOLIO  MANAGERS" IN THE SECTION
ENTITLED  "MANAGEMENT"  ON PAGE 32 OF THE  PROSPECTUS IS REMOVED IN ITS ENTIRETY
AND REPLACED WITH THE FOLLOWING:



         BOSTON PARTNERS LONG/SHORT EQUITY FUND

                  Robert T. Jones is the primary  portfolio manager for the Fund
         and Harry Rosenbluth is the secondary portfolio manager. Mr. Jones is a
         senior portfolio manager employed by the Adviser and is a member of the
         Adviser's Equity Strategy Committee.  Mr. Jones oversees the investment
         activities of the Adviser's  long/short  strategy  products  which,  in
         addition to the Fund,  includes two similar limited partnership private
         investment funds, two separately  managed accounts and an offshore fund
         of the Adviser.  Prior to taking on day to day responsibilities for the
         Long/Short  Equity Fund,  Mr. Jones served as portfolio  manager of the
         large cap value and large cap focused  institutional  equity portfolios
         in addition to serving as the  Adviser's  Director of Research.  Before
         joining the Adviser in April 1995, Mr. Jones spent seven years with The
         Boston Company Asset Management,  Inc., most recently as Vice President
         and Equity Portfolio Manager managing  institutional separate accounts.
         Mr. Jones has over sixteen years of investment experience and is a CFA.
         See  "BOSTON  PARTNERS  MID CAP VALUE FUND" for  information  about Mr.
         Rosenbluth.  For the fiscal  year ended  August  31,  2004,  the Boston
         Partners  Long/Short  Equity Fund paid 2.07% (expressed as a percentage
         of average net assets) to the Adviser for its services.



               PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE.


                                 BOSTON PARTNERS
                                 FAMILY OF FUNDS

                     BOSTON PARTNERS LONG/SHORT EQUITY FUND

                  (INVESTMENT PORTFOLIO OF THE RBB FUND, INC.)

                               INSTITUTIONAL CLASS

    Supplement dated September 15, 2004 to Prospectus dated December 31, 2003
                         as supplemented April 26, 2004

         THE   SUB-PARAGRAPH   OF  THE  PROSPECTUS   ENTITLED  "BOSTON  PARTNERS
LONG/SHORT  EQUITY FUND" UNDER THE CAPTION  "PORTFOLIO  MANAGERS" IN THE SECTION
ENTITLED  "MANAGEMENT"  ON PAGE 32 OF THE  PROSPECTUS IS REMOVED IN ITS ENTIRETY
AND REPLACED WITH THE FOLLOWING:



         BOSTON PARTNERS LONG/SHORT EQUITY FUND

                  Robert T. Jones is the primary  portfolio manager for the Fund
         and Harry Rosenbluth is the secondary portfolio manager. Mr. Jones is a
         senior portfolio manager employed by the Adviser and is a member of the
         Adviser's Equity Strategy Committee.  Mr. Jones oversees the investment
         activities of the Adviser's  long/short  strategy  products  which,  in
         addition to the Fund,  includes two similar limited partnership private
         investment funds, two separately  managed accounts and an offshore fund
         of the Adviser.  Prior to taking on day to day responsibilities for the
         Long/Short  Equity Fund,  Mr. Jones served as portfolio  manager of the
         large cap value and large cap focused  institutional  equity portfolios
         in addition to serving as the  Adviser's  Director of Research.  Before
         joining the Adviser in April 1995, Mr. Jones spent seven years with The
         Boston Company Asset Management,  Inc., most recently as Vice President
         and Equity Portfolio Manager managing  institutional separate accounts.
         Mr. Jones has over sixteen years of investment experience and is a CFA.
         See  "BOSTON  PARTNERS  MID CAP VALUE FUND" for  information  about Mr.
         Rosenbluth.  For the fiscal  year ended  August  31,  2004,  the Boston
         Partners  Long/Short  Equity Fund paid 2.07% (expressed as a percentage
         of average net assets) to the Adviser for its services.

               PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE.