Supplement, dated January 21, 2000, to the Prospectus, dated May 1, 1999,
                                       of
                     Seligman Portfolios, Inc. (the "Fund")


The following supersedes the related information set forth in the Fund's
prospectus.

On  January  21,  2000,  pursuant  to  authorization  from the  Fund's  Board of
Directors,   J.  &  W.  Seligman  &  Co.  Incorporated,   manager  of  the  Fund
("Seligman"), gave notice to Henderson Investment Management Limited ("HIML") of
its termination, effective as of the close of business on March 31, 2000, of the
Subadvisory  Agreement  between  Seligman  and HIML in respect  of the  Seligman
Henderson  International   Portfolio,   the  Seligman  Henderson  Global  Growth
Opportunities  Portfolio, and the Seligman Henderson Global Technology Portfolio
(the  "Portfolios").  At this time, HIML will continue to act as subadvisor with
respect to the Seligman Henderson Global Smaller Companies Portfolio.

International advisory services will be provided to the Portfolios by Seligman's
Global Growth Team or Global  Technology  Team, as described  below.  During the
notice  period,  HIML will continue to provide the  Portfolios  with  investment
advice,  research  and  assistance  with  respect to their  non-US  investments,
subject to Seligman's  overall  supervision.  Following the close of business on
March  31,  2000,  Seligman  will  assume  full  responsibility  for the  non-US
investments of the Portfolios.

Seligman's  Global  Growth  Team  will  be  responsible  for  the  international
investments of the International  Portfolio and the Global Growth  Opportunities
Portfolio.  The Global Growth Team is co-headed by Ms. Marion S.  Schultheis and
Mr. Jack P. Chang.

Ms. Schultheis joined Seligman in May 1998 as a Managing Director. She is a Vice
President  of the Fund and has been  Co-Portfolio  Manager of the Global  Growth
Opportunities   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  Capital  Portfolio  and the
Large-Cap  Growth  Portfolio of the Fund; and she manages Seligman Capital Fund,
Inc. and Seligman Growth Fund,  Inc. Ms.  Schultheis is also a Vice President of
Seligman  Global Fund Series,  Inc. and  co-manages  its Seligman  International
Growth Fund and Seligman Global Growth Fund.

Mr. Chang joined Seligman on September 20, 1999 as a Managing Director.  He is a
Vice President of the Fund.  Prior to joining  Seligman,  Mr. Chang was a Senior
Vice President and Portfolio Manager at Putnam Investment Management since 1997.
Prior thereto,  he was a Portfolio Manager with Columbia Management Company from
1993 to 1997, and a Senior Analyst and Portfolio Manager with Scudder, Stevens &
Clark from 1989 to 1993. Mr. Chang is also a Vice  President of Seligman  Global
Fund Series,  Inc. and  co-manages  its Seligman  International  Growth Fund and
Seligman Global Growth Fund.




The Global  Technology Team, headed by Mr. Paul H. Wick, will be responsible for
the international  investments of the Global Technology  Portfolio.  Mr. Wick, a
Managing  Director of  Seligman,  is a Vice  President  of the Fund and has been
Co-Portfolio Manager of the Global Technology Portfolio since its inception. Mr.
Wick has been a Managing  Director of Seligman since January 1995 and a Director
of Seligman since November  1997. Mr. Wick also manages the  Communications  and
Information  Portfolio  of the  Fund.  Mr.  Wick has been a Vice  President  and
Portfolio  Manager of Seligman  Communications  and Information Fund, Inc. since
January 1990 and December 1989,  respectively.  Mr. Wick is a Vice President and
Co-Portfolio  Manager of Seligman New Technologies  Fund, Inc. He is also a Vice
President of Seligman Global Fund Series,  Inc. and Co-Portfolio  Manager of its
Seligman Global Technology Fund.

Ms. Kei Yamamoto,  a Senior Vice President of Seligman,  is Co-Portfolio Manager
of the Global  Technology  Portfolio.  She is a Vice  President of the Fund. Ms.
Yamamoto  joined  Seligman in May 1998 as a Vice President and has been a Senior
Vice President since January 2000. Prior to joining  Seligman,  Ms. Yamamoto was
an Associate  Portfolio Manager at Oppenheimer Funds, Inc. from 1997 to 1998 and
an Assistant  Portfolio  Manager at Franklin  Templeton Group from 1994 to 1997.
She  is  also a  Vice  President  of  Seligman  Global  Fund  Series,  Inc.  and
Co-Portfolio Manager of its Seligman Global Technology Fund.

Mr. Steven A. Werber,  a Vice President of the Fund, is Co-Portfolio  Manager of
the Global Technology Portfolio.  Mr. Werber joined Seligman on January 10, 2000
as a Senior Vice President. Prior to joining Seligman, Mr. Werber was an Analyst
and Portfolio Manager at Fidelity  Investments  International  since 1996. Prior
thereto,  he was an Associate at Goldman Sachs  International from 1992 to 1996.
Mr.  Werber is also a Vice  President of Seligman  Global Fund Series,  Inc. and
Co-Portfolio Manager of its Seligman Global Technology Fund.

The Fund has also  removed  "Henderson"  from the names of each of its  affected
portfolios.  In addition, the Seligman  International  Portfolio has changed its
name to the "Seligman  International  Growth  Portfolio" and the Seligman Global
Growth  Opportunities  Portfolio  has changed its name to the  "Seligman  Global
Growth Portfolio."

                                 _______________


The following supersedes the related information on page P-39, under the Section
"Management of the Fund," in the Fund's prospectus.

Each of the Seligman International Growth Portfolio,  the Seligman Global Growth
Portfolio,  the Seligman  Global  Technology  Portfolio and the Seligman  Global
Smaller  Companies  Portfolio  pays Seligman a fee for its  management  services
equal to a percentage of the Portfolio's  average daily net assets. The fee rate
declines as each Portfolio's net assets  increase.  The management fee rate with
respect to the Global  Technology  Portfolio is equal to an annual rate of 1.00%
of average  daily net assets on the first $2 billion,  .95% of average daily net
assets on the next $2 billion and .90% of average  daily net assets in excess of
$4 billion.  The  management fee rate with respect to the  International  Growth
Portfolio,  the  Global  Growth  Portfolio  and  the  Global  Smaller  Companies
Portfolio is equal to an annual rate of 1.00% of average daily net assets on the
first $1  billion,  .95% of average  daily net assets on the next $1 billion and
 .90% of average daily net assets in excess of $2 billion.


SUPP1-1/00






                       Supplement, dated January 21, 2000,
         to the Statement of Additional Information, dated May 1, 1999,
                      as Supplemented on December 15, 1999
                                       of
                     Seligman Portfolios, Inc. (the "Fund")


The  following  supersedes  the  related  information  set  forth in the  Fund's
statement of additional information.

On  January  21,  2000,  pursuant  to  authorization  from the  Fund's  Board of
Directors,  J. & W.  Seligman & Co.  Incorporated  ("Seligman"),  manager of the
Fund, gave notice to Henderson  Investment  Management  Limited  ("HIML") of its
intent to  terminate  the  Subadvisory  Agreement  between  Seligman and HIML in
respect  of  the  Seligman  Henderson  International   Portfolio,  the  Seligman
Henderson  Global Growth  Opportunities  Portfolio,  and the Seligman  Henderson
Global Technology  Portfolio (the "Portfolios").  During the notice period, HIML
will continue to provide the Portfolios  with  investment  advice,  research and
assistance  with  respect to their  non-US  investments,  subject to  Seligman's
overall supervision. Following the close of business on March 31, 2000, Seligman
will assume full responsibility for the non-US investments of the Portfolios.

HIML will continue to act as subadvisor  with respect to the Seligman  Henderson
Global Smaller Companies Portfolio and to receive a fee from Seligman equal to
an annual rate of .50% of the Smaller Companies Portfolio's average
daily net assets under its supervision.

                                 _______________

The Fund has also  removed  "Henderson"  from the names of each of its  affected
portfolios.  In addition, the Seligman  International  Portfolio has changed its
name to the "Seligman  International  Growth  Portfolio" and the Seligman Global
Growth  Opportunities  Portfolio  has changed its name to the  "Seligman  Global
Growth Portfolio."

SUPP1-1/00