<PAGE>
Filed Pursuant to Rule 497(e)
Registration File No.: 33-37562
SUPPLEMENT TO THE PROSPECTUS OF
MORGAN STANLEY DEAN WITTER MULTI-STATE MUNICIPAL SERIES TRUST
DATED MARCH 30, 1999
On January 26, 2000, the Board of Trustees of Morgan Stanley Dean Witter
Multi-State Municipal Series Trust (the "Fund") approved Agreements and Plans
of Reorganization by and between certain of the Fund's Series (each, the
"merging Series") and certain other Morgan Stanley Dean Witter Funds (each,
the "acquiring Fund"), pursuant to which substantially all of the assets of
the merging Series would be combined with those of the acquiring Fund and
shareholders of the merging Series would become shareholders of the acquiring
Fund receiving Class D shares of the acquiring Fund equal to the value of
their holdings in the merging series (each, a "Reorganization") as follows:
MERGING SERIES ACQUIRING FUND
- ------------------------ -----------------------------------
California Series -- Morgan Stanley Dean Witter
California Tax-Free Income Fund
Massachusetts Series -- Morgan Stanley Dean Witter
Tax-Exempt Securities Trust
Michigan Series -- Morgan Stanley Dean Witter
Tax-Exempt Securities Trust
Minnesota Series -- Morgan Stanley Dean Witter
Tax-Exempt Securities Trust
New York Series -- Morgan Stanley Dean Witter
New York Tax-Free Income Fund
Ohio Series -- Morgan Stanley Dean Witter
Tax-Exempt Securities Trust
Each Reorganization is subject to the approval of shareholders of the
applicable merging Series at a special meeting of shareholders scheduled to
be held on June 22, 2000. A proxy statement formally detailing the proposal,
the reasons for the Trustees' action and information concerning the acquiring
Fund will be distributed to shareholders of each merging Series.
January 26, 2000
