<PAGE>
Filed Pursuant to Rule 497(e)
Registration File No.: 2-82510
SUPPLEMENT TO THE PROSPECTUS OF
MORGAN STANLEY DEAN WITTER
VARIABLE INVESTMENT SERIES
DATED AUGUST 5, 1999
The sentences pertaining to the Pacific Growth Portfolio of the Fund in
the section of the Prospectus entitled "Portfolio Management" are hereby
replaced by the following:
PACIFIC GROWTH PORTFOLIO -- Ashutosh Sinha, Vice President of the
Sub-Advisor, has been a primary portfolio manager of the Portfolio since
November 1998. John R. Alkire, a Managing Director of the Sub-Advisor and
President of Morgan Stanley Investment Advisory, Japan, has been a primary
portfolio manager of the Portfolio since May 1999. Prior to joining the
Sub-Advisor in June 1995, Mr. Sinha was an analyst at SBI Funds Management
Ltd. (1993-1995). Mr. Alkire has been a portfolio manager with the
Sub-Advisor for over five years.
January 26, 2000
