KRF3 Acquisition Company, L.L.C.
                          One Beacon Street, Suite 1500
                           Boston, Massachusetts 02108

May 14, 1999

To Unitholders in Krupp Realty Fund, Ltd. - III

Re: Offer to Purchase Limited Partnership Interests

Dear Investor:

KRF3 Acquisition Company, L.L.C. (the "Purchaser") is seeking to buy all of your
Investor  Limited  Partnership  Interests  (the  "Units") in Krupp  Realty Fund,
Ltd.-III (the  "Partnership")  for $550.00 per Unit in cash (the "Offer Price"),
less any cash  distributions  made by the Partnership to Unitholders on or after
the date of this letter.

The accompanying  materials contain  important  information about the Offer, and
you should read them  carefully  before  making a decision to tender your Units.
Among other  things,  please  consider the following  points in  evaluating  our
offer:

o    Higher  Price than  Recent  Madison  Offer.  We believe  that the  recently
     initiated Offer to Purchase made by Madison Liquidity Investors 104, LLC of
     $425 per Unit is  inadequate.  Our Offer  Price of $550.00  per Unit is 29%
     higher, which we believe is a fair offer.

o    Market  Developments.  The apartment complexes owned by the Partnership are
     facing recent increased  competition  from newly  constructed and renovated
     residential  units in their markets.  To meet this  challenge,  substantial
     capital improvements may be required for such properties. Implementation of
     these improvements could require the investment of additional equity,  bank
     borrowings and/or a discontinuation of the future cash distributions by the
     Partnership to Unitholders,  and the Partnership's  ability to finance such
     improvements is uncertain.  Consequently, the offer presents an opportunity
     for  Unitholders  who do not wish to continue to  participate  in the risks
     associated  with the  ownership of  multifamily  properties,  including the
     risks  associated  with  these  recent  developments  in the  Partnership's
     markets.

o    Elimination of Uncertainty and Increased  Liquidity.  Selling your Units in
     the offer  will  eliminate  the  uncertainties  relating  to the amount and
     timing of any  liquidation of the  Partnership,  which will depend upon the
     then-current markets for the properties, as well as upon amounts that would
     be required to be reserved  to satisfy  contingent  liabilities  associated
     with  these  sales.  Furthermore,  by  selling  the  units  for  cash  now,
     Unitholders  will enjoy the  ability to  redeploy  investment  assets  into
     alternative and potentially more liquid investments.






o    Fast,  Commission-free  Sale. Because there is no formal trading market for
     the Units,  they can be difficult to sell.  Our offer provides you with the
     opportunity  to  immediately  sell your Units for what we believe is a fair
     price without the  commissions  or broker's fee of a secondary  market sale
     and we will pay the $50  transfer  fee charged by the  Partnership  usually
     paid by the seller.

o    You Will Forego Future Benefits of Owning Units.  Of course,  if you tender
     your Units you will give up the  opportunity  to  participate in any future
     benefits  from  the  ownership  of  Units,   including   potential   future
     distributions by the  Partnership,  and the purchase price per Unit payable
     to you may be less than the total amount which might  otherwise be received
     by  you  with  respect  to  the  Units  over  the  remaining  term  of  the
     Partnership.

o    The Purchaser Seeks to Make a Profit and has a Conflict.  Bear in mind that
     the  Purchaser  is making the offer with the  intention  of making a profit
     from its ownership of the Units.  There is an inherent conflict between our
     desire to  purchase  Units at a low price and your desire to sell them at a
     high price. Moreover, the Purchaser is an affiliate of the General Partners
     of the Partnership, and has certain conflicts in connection with the offer,
     which are  described  in the  enclosed  materials.  When the  assets of the
     Partnership are ultimately sold, the return to Unitholders  could be higher
     or lower than the Offer Price. The Purchaser will benefit to the extent, if
     any,  that the amount per Unit it receives in the  liquidation  exceeds the
     Offer Price.

o    No  Independent  Evaluation.  No  independent  person has been  retained to
     evaluate or render any opinion  with  respect to the  fairness of the Offer
     Price.

o    Conditions of Sale. The Purchaser's obligation to purchase Units is subject
     to its right to  purchase  no less than a majority  of the total  number of
     outstanding Units (the "Minimum Condition") as well as other conditions set
     forth in the Offer to Purchase.

Unitholders  who  choose  to  tender  their  Units  to us will be paid  promptly
following (1) receipt of a valid,  properly executed Agreement of Assignment and
Transfer  (see  the  yellow  document  enclosed)  and  (2)  satisfaction  of the
conditions  outlined in the Offer to Purchase,  including the Minimum Condition.
All sales of Units will be irrevocable by you, subject to Section 4.
Withdrawal Rights of "The Offer" section of the Offer to Purchase.

A  comprehensive  discussion  of the  terms  of the  offer  can be  found in the
accompanying Offer to Purchase.  Unitholders are urged to consider carefully all
the information contained in this packet before accepting the offer. If you wish
to accept our offer,  please  complete and Medallion  Signature  Guarantee (this
must be done by your  broker or a bank where you have an account)  the  enclosed
yellow  Agreement  of  Assignment  and  Transfer  and return it in the  enclosed
envelope.

Our offer will expire at midnight New York City time on June 11, 1999 unless the
offer is extended. We encourage you to act promptly.

Please call us at (800) 605-6774, or send a fax to (617) 574-8312. Thank you for
your consideration of our offer.

                                   KRF3 Acquisition Company L.L.C.