AIMCO

                             AIMCO PROPERTIES, L.P.
                           c/o The Altman Group, Inc.
                                  P.O. Box 238
                               Lyndhurst, NJ 07071
                                 (800) 467-0821

                              AN IMPORTANT REMINDER

                                                                  March 15, 2005

Dear Limited Partner:

      We recently mailed you tender offer documents offering to purchase your
units of limited partnership interest in Century Properties Fund XV for
$89.64 per unit in cash. Our offer was made upon the terms and subject to the
conditions set forth in the Offer to Purchase, dated February 16, 2005, and in
the related Letter of Transmittal (collectively, together with any supplements
or amendments, our "Offer").

      WE HAVE EXTENDED OUR OFFER UNTIL MIDNIGHT, NEW YORK CITY TIME, ON MARCH
28, 2005, AND HAVE ISSUED A PRESS RELEASE ANNOUNCING THE EXTENSION. Our Offer
was previously scheduled to expire on March 17, 2005.

      Our Offer provides you with an opportunity to:

      -     GAIN LIQUIDITY FOR YOUR INVESTMENT WHICH YOU MAY NOT HAVE HAD
            PREVIOUSLY, AND

      -     TO ELIMINATE THE COST AND RECORD KEEPING ASSOCIATED WITH LIMITED
            PARTNERSHIP TAX REPORTING.

      If you retain your units, you will continue to be a limited partner. If
you elect to remain in the partnership until termination, you will continue to
participate in the partnership distributions, if any, and the tax effects of the
partnership's results.

      Please remember, that to accept our Offer, you must complete and sign the
enclosed Letter of Transmittal in accordance with its instructions, which must
be received by our information agent, The Altman Group, Inc., by March 28, 2005.
If you have already tendered your units, you need not do anything at this time.

      If you have any questions, please contact the Information Agent, toll
free, at (800) 467-0821.

                                                          Sincerely,

                                                          AIMCO Properties, L.P.