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                                                                    Exhibit 99.3

                              NEOPROBE CORPORATION

                                  AMENDMENT TO

                          AMENDED AND RESTATED BY-LAWS

                              ADOPTED MAY 30, 1996





     Section 2 of Article III of the By-laws of the Corporation was amended by
adding the following paragraph at the end thereof:

         Notwithstanding any other provision set forth in the By-laws of the
Corporation, the board of directors shall be divided into three classes; the
term of office of those of the first class to expire at the annual meeting next
ensuing; of the second class one year thereafter; of the third class two years
thereafter; and at each annual election held after the initial adoption of this
by-law by the stockholders and the election of directors held at the meeting at
which this by-law is adopted, directors shall be chosen for a full term of three
years, as the case may be, to succeed those whose terms expire. When this by-law
is initially adopted by the stockholders, the board of directors shall consist
of nine members and each class shall consist of three members. Thereafter, the
board of directors may fix the total number of directors constituting the full
board of directors and the number of directors in each class, but the total
number of directors shall not exceed seventeen (17) nor shall the number of
directors in any class exceed six (6). Subject to the foregoing, the classes of
directors need not have the same number of members. No reduction in the total
number of directors or in the number of directors in any class shall be
effective to remove any director or to reduce the term of any director. If the
board of directors increases the number of directors in a class, it may fill the
vacancy created thereby for the full remaining term of a director in that class
even though such term may extend beyond the next annual election. The board of
directors may fill any vacancy occurring for any other reason for the full
remaining term of the director whose death, resignation or removal caused the
vacancy, even though such term may extend beyond the next annual election.