<PAGE>
Filed Pursuant to Rule 497(e)
Registration File No.: 333-18953
SUPPLEMENT TO THE PROSPECTUS OF
MORGAN STANLEY DEAN WITTER PRIME INCOME TRUST
DATED JANUARY 25, 1999
The fourth paragraph of the section entitled "Investment Advisory
Agreement" in the above Prospectus is revised to reflect that, effective May 1,
1999, the Trustees of the Trust have amended the Trust's Investment Advisory
Agreement to reduce the compensation received by the Investment Advisor under
the Agreement for assets exceeding $2.5 billion, so that the compensation under
the Agreement is calculated daily by applying the following annual rates to the
Trust's net assets determined as of the close of each business day: 0.90% of
the portion of daily net assets not exceeding $500 million; 0.85% of the next
$1 billion; 0.825% of the next $1 billion; and 0.80% of the portion of daily
net assets exceeding $2.5 billion.
May 1, 1999
