FIFTH AMENDMENT OF LEASE


         THIS FIFTH AMENDMENT OF LEASE, made this 13th day of December, 1996,
between Glaxo Wellcome Inc., successor to Glaxo Inc., a North Carolina
Corporation, successor in interest to Imperial Center Partnership and Petula
Associates, Ltd., hereinafter called "Landlord," and Embrex, Inc., a North
Carolina Corporation, hereinafter called "Tenant," which terms "Landlord" and
"Tenant" shall include, whenever the context admits or requires, singular or
plural, and the heirs, legal representatives, successors and assigns of the
respective parties.

                                   WITNESSETH:

         WHEREAS, by Lease Agreement dated December 9, 1986, First Amendment of
Lease dated June 11, 1987, Second Amendment of Lease dated December 1, 1988,
Third Amendment of Lease dated May 2, 1989, and Fourth Amendment of Lease
bearing execution dates of September 23, 1994 for Tenant and October 5, 1994 for
Landlord, hereinafter collectively referred to as the "Lease," Tenant has leased
and demised certain premises situated at 1035 Swabia Court in Imperial Center
Business Park, County of Durham, State of North Carolina, for an initial term of
ten (10) years, subject to the covenants and conditions particularly set forth
in said Lease; and

         WHEREAS, at the end of the initial term Tenant has the option to
exercise an extension of the Lease for an additional five (5) year period; and

         WHEREAS, the parties desire to amend the Lease to extend the term for
an additional five (5) years, subject to the terms and conditions set forth
below.

         NOW THEREFORE, in consideration of the sum of One and No/100 Dollars
($1.00), and other good and valuable consideration, the receipt and sufficiency
whereof are hereby acknowledged, the parties hereto agree, each with the other,
as follows:

1.       PARAGRAPH 1.  PREMISES is hereby amended to read:

                  1.       PREMISES.  That the Landlord,  in consideration of 
                  the covenants of the Tenant, does hereby lease and demise unto
                  said  Tenant,  and the Tenant  does hereby  agree to take and 
                  lease from the  Landlord  for the term hereinafter specified, 
                  the  following described premises:

                           Warehouse and manufacturing and office space
                           containing approximately 23,209 square feet situated
                           at 1035 Swabia Court, Morrisville, County of Durham,
                           State of North Carolina, and more particularly
                           designated in Exhibit "A" attached hereto and
                           incorporated herein.

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2.       EXHIBIT "A" of the Lease is hereby amended by substituting  Exhibit "A"
         attached  hereto and  incorporated herein by reference.

3.       The first sentence of PARAGRAPH 2.  TERM is hereby amended to read:

                  2. TERM. For the Tenant to have and hold the leased premises
                  for an initial term of ten (10) years commencing the 1st day
                  of April, 1987, and ending the 31st day of March, 1997, and
                  for an additional term of five (5) years commencing on the 1st
                  day of April, 1997, and ending on the 31st day of March, 2002.

4.       Attachment 2-A is hereby amended to add the following rental
         information for the additional five (5) year period, which is
         referenced as years 11 through 15:


                                                        


 ----------------------- ---------------- ---------------------- ----------------------

   Additional
     Lease
    Period               P.S.F.              Monthly               Annually
- ----------------------- ---------------- ---------------------- ----------------------
- ----------------------- ---------------- ---------------------- ----------------------

Year 11                    $8.47             $16,381.69            $196,580.23
- ----------------------- ---------------- ---------------------- ----------------------
- ----------------------- ---------------- ---------------------- ----------------------

Year 12                    $8.72             $16,865.21            $202,382.48
- ----------------------- ---------------- ---------------------- ----------------------
- ---------------------- ---------------- ---------------------- ----------------------

Year 13                    $8.99             $17,387.41            $208,648.91
- ----------------------- ---------------- ---------------------- ----------------------
- ----------------------- ---------------- ---------------------- ----------------------

Year 14                    $9.26             $17,909.61            $214,915.34
- ----------------------- ---------------- ---------------------- ----------------------
- ----------------------- ---------------- ---------------------- ----------------------

Year 15                    $9.53             $18,431.81            $221,181.77
- ----------------------- ---------------- ---------------------- ----------------------




5.       PARAGRAPH 15.  INSURANCE is amended by deleting the fourth sentence, 
         which reads:

                  Tenant's pro rata share of said insurance cost shall be
                  computed using the ratio of the Leased Premises (13,470 S.F.)
                  to the total square footage of the building (49,200 S.F.).

         and inserting the following sentence in lieu thereof:

                  Tenant's pro rata share of said insurance cost shall be
                  29.435%, which is the ratio calculated by dividing the square
                  footage of the Leased Premises of 23,209 by the total square
                  footage of the building of 78,848.






6.       PARAGRAPH 18.  TAXES is amended by deleting the fifth sentence, which 
         reads:

                  Tenant's pro rata share of said ad valorem taxes shall be
                  computed using the ratio of the Leased Premises (13,470 S.F.)
                  to the total footage of the building (49,200 S.F.).

         and by inserting the following in lieu thereof:

                  Tenant's pro rata share of said ad valorem taxes shall be
                  29.435%, which is the ratio calculated by dividing the square
                  footage of the Leased Premises of 23,209 by the total square
                  footage of the building of 78,848.

7.       PARAGRAPH  30.  NOTICES is deleted in its  entirety, and the following 
         provision  is  inserted  in lieu thereof:

                  30. NOTICES. All notices, required or allowed hereunder, shall
                  be sent to the parties as provided herein, in writing, and
                  shall be delivered (i) personally, (ii) by registered or
                  certified mail, postage prepaid, return receipt requested,
                  (iii) by nationally recognized overnight courier service, or
                  (iv) by facsimile where such notice is electronically
                  confirmed as received and is followed by delivery of a copy of
                  such notice in a manner described in (i), (ii), or (iii), to
                  the following addresses of the respective parties:

                  If to Landlord:   Glaxo Wellcome Inc.
                                    Five Moore Drive
                                    Research Triangle Park, North Carolina 27709
                            ATTN:   Director of Real Estate
                  with a copy to:   General Counsel

                    If to Tenant:   Embrex, Inc.
                                    1035 Swabia Court
                                    Durham, North Carolina 27703

                  All notices shall be deemed communicated upon first delivery
                  to the address stated above as described in (i) - (iv) above.
                  A party may change its address listed above by notice to the
                  other party.






8.       PARAGRAPH 4 of the Fourth Amendment to Lease is amended by deleting
         from the first sentence the phrase, "over a five year period," and by
         deleting the last sentence, which reads:

                  At the end of the lease term Tenant will pay Landlord $12,753,
                  the unamortized portion of the balance on said lab furniture
                  and equipment.

         and inserting the following sentences at the end of PARAGRAPH 4:

                  In addition to all other rent due hereunder, Tenant shall pay
                  Landlord each month of years 11 through 15 of the Term, at the
                  same time it makes its rent payments, an additional sum of
                  $264.73 and in this manner at the end of year 15 will have
                  fully paid Landlord for the laboratory furniture and equipment
                  being purchased. All of Landlord's remedies for nonpayment of
                  rent shall also apply to the nonpayment of any monthly
                  installment of the laboratory furniture and equipment purchase
                  which is due but not made.

9.       It is  understood  and agreed that the First Right of Refusal set forth
         in Lease Addendum No. 4 and the Buyout Provision set forth in Lease 
         Addendum No. 3 are null and void and of no further force or effect.

         That except as herein modified, said Lease, as amended, shall remain in
full force and effect and the covenants and agreements contained herein shall
bind and inure to the benefit of the parties hereto, their heirs, personal
representatives, successors and assigns, and any number and gender shall include
the other number and gender.

         IN WITNESS WHEREOF, the parties hereto have executed this Fifth
Amendment of Lease.

LANDLORD:

GLAXO WELLCOME INC.


By:  /s/ Manuel C. Silva
     -------------------
Its   Vice President - Corporate Engineering
      --------------------------------------

         Attest:_______________________________      [Corporate Seal]
                  ______________ Secretary







TENANT:

EMBREX, INC.


By:  /s/ Randall L. Marcuson
Its   President and CEO

         Attest: Don T. Seaquist                              [Corporate Seal]
                 Corporate Secretary



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STATE OF ______________________     (Corporate Notary)
COUNTY OF ____________________

         I, ______________________, a Notary Public, certify that
_________________________ personally came before this day and acknowledged that
s/he is _________________ Secretary of ____________________________, a
Corporation, and that by authority duly given and as the act of the corporation,
the foregoing instrument was signed in its name by its ______________ President,
sealed with its corporate seal, and attested by him/herself as its
_________________ Secretary.

     WITNESS my hand and notarial seal this _____ day of _______________, 19___.

     My Commission Expires:____________           
     ______________________________
                                                         Notary Public








STATE OF NORTH CAROLINA             (Corporate Notary)
COUNTY OF DURHAM

         I, Colleen S. Loree, a Notary Public, certify that Don T. Seaquist
personally came before this day and acknowledged that he is Corporate Secretary
of Embrex, Inc., a Corporation, and that by authority duly given and as the act
of the corporation, the foregoing instrument was signed in its name by its
______________ President, sealed with its corporate seal, and attested by
him/herself as its Corporate Secretary.

      WITNESS my hand and notarial seal this 13th day of December, 1996.

      My Commission Expires: April 15, 2001                /s/ Colleen S. Loree
                             --------------                --------------------
                                                           Notary Public
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                 [Blueprint/architectural drawing appears here]

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