EXHIBIT 5.1

                             FOLEY, HOAG & ELIOT LLP
                             ONE POST OFFICE SQUARE
                        BOSTON, MASSACHUSETTS 02109-2170


                     TELEPHONE 617-832-1000         1747 PENNSYLVANIA AVE., N.W.
                     FACSIMILE 617-832-7000               WASHINGTON, D.C. 20006
                       http://www.fhe.com                      TEL: 202-223-1200
                                                               FAX: 202-785-6687



                                   May 6, 1999

WHITE PINE SOFTWARE, INC.
542 Amherst Street
Nashua, New Hampshire  03063

Ladies and Gentlemen:

         We have acted as counsel for White Pine Software, Inc., a Delaware
corporation (the "Company"), in connection with the preparation and filing with
the Securities and Exchange Commission under the Securities Act of 1933, as
amended, of a Registration Statement on Form S-8 (the "Registration Statement")
relating to the offering by the Company of 100,000 shares (the "Shares") of its
common stock, $.01 par value, issuable pursuant to the White Pine Software, Inc.
Amended and Restated 1996 Employee Stock Purchase Plan, as amended and restated
on December 16, 1998 (the "Plan").

         In arriving at the opinions expressed below, we have examined and
relied on the following documents:

         (i)      the Registration Statement;

         (ii)     the Plan;

         (iii)    the Amended and Restated Certificate of Incorporation of the
                  Company;

         (iv)     the By-Laws of the Company, as amended as of the date hereof;
                  and

         (v)      the records of meetings and consents of the Board of Directors
                  and stockholders of the Company provided to us by the Company.

         In addition, we have examined and relied on the originals or copies
certified or otherwise identified to our satisfaction of all such other records,
documents and instruments of the Company 




WHITE PINE SOFTWARE, INC.
May 6, 1999
Page Two


and such other persons, and we have made such investigations of law, as we have
deemed appropriate as a basis for the opinions expressed below. We have assumed
the genuineness of all signatures and the authenticity of all documents
submitted to us as originals and the conformity to the original documents of all
documents submitted to us as certified or photostatic copies.

         We express no opinion other than as to the General Corporation Law of
the State of Delaware. 

         Based upon the foregoing, we are of the opinion that:

         1.       The Company has the corporate power necessary to issue the 
                  Shares under the Plan, as contemplated by the Registration 
                  Statement.

         2.       The Shares have been duly authorized and, when issued against
                  payment of the agreed consideration therefor in accordance
                  with the respective exercise prices therefor as described in
                  the Plan, will be validly issued, fully paid and
                  non-assessable.

         We consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement.

                                       Very truly yours,

                                       FOLEY, HOAG & ELIOT LLP


                                       By      /s/ Mark L. Johnson       
                                           --------------------------------
                                           A Partner