COLUMBIA FUNDS SERIES TRUST
                      MORTGAGE- AND ASSET-BACKED PORTFOLIO
                                 (THE PORTFOLIO)

                         SUPPLEMENT DATED MARCH 13, 2007
                      TO PROSPECTUSES DATED AUGUST 1, 2006

Effective immediately, the prospectus for the Portfolio is hereby supplemented
as follows:

1.   By adding the following at the end of the first paragraph under the heading
     "Principal investment strategies":

          The Portfolio may participate in mortgage dollar rolls up to the
          amount of allowable investments in mortgage-backed securities and
          limited to the Portfolio's current position in mortgage-backed
          securities. The Portfolio may roll all, a portion, or none of the
          Portfolio's current position in mortgage-backed securities.

2.   By adding the following as the last bullet point under the heading
     "Principal risks and other things to consider":

          -    MORTGAGE DOLLAR ROLLS - Mortgage dollar rolls are transactions in
               which the Portfolio sells mortgage-backed securities to a dealer
               and simultaneously agrees to purchase similar securities in the
               future at a predetermined price. These transactions simulate an
               investment in mortgage-backed securities and have the potential
               to enhance the Portfolio's returns and reduce its administrative
               burdens, compared with holding mortgage-backed securities
               directly. Mortgage dollar rolls involve the risks that the market
               value of the securities the Portfolio is obligated to repurchase
               may decline below the repurchase price, or that the other party
               may default on its obligations. These transactions may increase
               the Portfolio's portfolio turnover rate.




INT-47/129701-0307