Supplement, dated March 2, 2000, to the Prospectus, dated May 1, 1999,
                    of Seligman Portfolios, Inc. (the "Fund")
                                on behalf of its
                         Seligman Frontier Portfolio and
                   Seligman Global Smaller Companies Portfolio


Seligman Frontier Portfolio - P-14

Effective  March 2, 2000, the following  supersedes and replaces the information
contained in the paragraph set forth on page P-14 of the Fund's Prospectus under
the caption "Portfolio Management."

The Frontier  Portfolio is managed by the Seligman Small Company Team, headed by
Mr. Mark J. Cunneen.  Mr. Cunneen joined Seligman on March 1, 2000 as a Managing
Director.  Prior to joining Seligman, Mr. Cunneen had been Senior Vice President
- - Head of Small Cap Group at Alliance  Capital  Management  since  January 1999.
Prior thereto, he was with Chancellor Capital Management and its successor firms
as Managing  Director and Head of the Small Cap Group from March 1997 to January
1999,  and as a portfolio  manager in the Small Cap Group from  December 1992 to
March 1997.  (Chancellor Capital Management was acquired by LGT Asset Management
in October  1996,  which was acquired by Invesco in May 1998.) Mr.  Cunneen also
co-manages the Seligman Global Smaller  Companies  Portfolio of the Fund; and he
manages  Seligman  Frontier Fund,  Inc. and co-manages  Seligman  Global Smaller
Companies Fund, a series of Seligman Global Fund Series, Inc.

                                     * * * *

Seligman Global Smaller Companies Portfolio - P-20

Effective  March 2, 2000, the following  supersedes and replaces the information
contained  in the  second  paragraph  set  forth  on  page  P-20  of the  Fund's
Prospectus under the caption "Portfolio Management."

The Seligman  Small Company Team is headed by Mr. Mark J. Cunneen.  Mr.  Cunneen
joined  Seligman  on March 1,  2000 as a  Managing  Director.  Prior to  joining
Seligman,  Mr.  Cunneen had been Senior Vice President - Head of Small Cap Group
at Alliance Capital  Management  since January 1999. Prior thereto,  he was with
Chancellor  Capital  Management and its successor firms as Managing Director and
Head of the Small Cap Group from March 1997 to January 1999,  and as a portfolio
manager in the Small Cap Group from  December  1992 to March  1997.  (Chancellor
Capital  Management was acquired by LGT Asset  Management in October 1996, which
was  acquired by Invesco in May 1998.) Mr.  Cunneen  also  manages the  Seligman
Frontier  Portfolio of the Fund; and he manages Seligman Frontier Fund, Inc. and
co-manages  Seligman Global Smaller  Companies Fund, a series of Seligman Global
Fund Series, Inc.


SUPP1-3/00