Supplement, dated October 5, 2000, to the
                         Prospectus, dated May 1, 2000,
                    of Seligman Portfolios, Inc. (the "Fund")
                                on behalf of its
               Seligman Frontier Portfolio ("Frontier Portfolio")
          Seligman Global Growth Portfolio ("Global Growth Portfolio")
                  Seligman Global Smaller Companies Portfolio
                     ("Global Smaller Companies Portfolio")
   Seligman International Growth Portfolio ("International Growth Portfolio")


Frontier Portfolio and Global Smaller Companies Portfolio:

     The definition of "smaller companies" appearing in the highlighted boxes on
pages P-13 and P-19, respectively,  of the Fund's Prospectus has been revised as
follows:

                 "Smaller  Companies:  Companies  with  market
                  capitalization,  at the  time  of purchase by
                  the Portfolio, of $2 billion or less."


Global Growth Portfolio and International Growth Portfolio:

     The  following   information   replaces  the  paragraphs  under  "Portfolio
Management"  under the separate  sections of "Global  Growth  Portfolio" on page
P-18 and "International Growth Portfolio" on page P-34 of the Fund's Prospectus:

The Portfolio is managed by the Seligman's  Global Growth Team,  which is headed
by Ms. Marion S.  Schultheis.

Ms. Schultheis joined Seligman in May 1998 as a Managing Director. She is a Vice
President of the Fund and has been Portfolio  Manager of the Portfolio since May
1998.  Prior to joining  Seligman,  Ms.  Schultheis  was a Managing  Director at
Chancellor LGT from October 1997 to May 1998 and Senior Portfolio Manager at IDS
Advisory  Group Inc.  from  August 1987 to October  1997.  Ms.  Schultheis  also
manages the Seligman  Capital  Fund,  Inc. and  Seligman  Growth Fund,  Inc. Ms.
Schultheis is also a Vice  President of Seligman  Global Fund Series,  Inc., and
the Global  Growth Team,  which she heads,  manages its  Seligman  International
Growth  Fund  and  Global  Growth  Fund.

Prior to March 31, 2000, Henderson  Investment  Management Limited (HIML) served
as a subadviser to the Portfolio.  HIML,  established in 1984, is a wholly owned
subsidiary of Henderson,  plc, a United Kingdom corporation.  For the year ended
December 31, 1999,  Seligman  paid HIML a fee for its services in respect of the
Portfolio based on the assets under HIML's supervision.  This fee did not affect
the fees paid by the Portfolio.


SP1S1-10/2000