EXHIBIT 5



             [LETTERHEAD OF BALLARD SPAHR ANDREWS & INGERSOLL, LLP
                                 APPEARS HERE]



                                   June 4, 1999



Boston Life Sciences, Inc.
31 Newbury Street
Suite 300
Boston, Massachusetts   02116


     Re:  Boston Life Sciences, Inc. 1998 Omnibus Stock Option Plan (the "Plan")
          Registration Statement on Form S-8
          ---------------------------------------------------------------------

Gentlemen:

         We have acted as counsel to Boston Life Sciences, Inc. (the "Company")
in connection with the registration under the Securities Act of 1933, as
amended, of 500,000 shares of common stock of the Company, par value $.01 per
share (the "Shares"), issuable under the Plan.

         The opinion expressed below is based on the assumption that the
Registration Statement on Form S-8 with respect to the Shares issuable upon the
exercise of the options granted under the Plan will have been filed by the
Company with the Securities and Exchange Commission before any of the Shares are
issued and that the persons acquiring the Shares will receive a prospectus
containing all of the information required by Part I of Form S-8 before
acquiring such Shares.

         In rendering our opinion, we have reviewed the Plan and such
certificates, documents, corporate records and other instruments as in our
judgment are necessary or appropriate to  enable us to render the opinion
expressed below.  In giving this opinion, we are assuming the authenticity of
all instruments presented to us as originals, the conformity with the originals
of all instruments presented to us as copies and the genuineness of all
signatures.

         Based upon the foregoing, we are of the opinion that the Shares, when
issued in accordance with the terms of the Plan, will be legally issued, fully
paid and non-assessable.


Boston Life Sciences, Inc.
June 4, 1999
Page 2

         This opinion is limited to the matters expressly stated herein.  No
implied opinion may be inferred to extend this opinion beyond the matters
expressly stated herein.  We do not undertake to advise you or anyone else of
any changes in the opinions expressed herein resulting from changes in law,
changes in facts or any other matters that hereafter might occur or be brought
to our attention.

         We consent to the filing of this opinion as Exhibit 5 to the
Registration Statement.

                                   Very truly yours,
                                   /s/ Ballard Spahr Andrews & Ingersoll, LLP