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                           WARRANT PURCHASE AGREEMENT


                              Warrants to Purchase
                              500,000 Shares of the
                     Common Stock of Boston Biomedica, Inc.






                             Dated: August 18, 1999






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<PAGE>


                           WARRANT PURCHASE AGREEMENT
                           --------------------------

                                TABLE OF CONTENTS
                                -----------------

ARTICLE 1.  DESCRIPTION OF PROPOSED FINANCING..................................1

1.1 Authorization of Warrants..................................................1

1.2 Purchase and Sale of Warrants..............................................1

1.3 Closing....................................................................1


ARTICLE 2.  REPRESENTATIONS AND WARRANTIES OF THE COMPANY......................2

2.1 Organization and Qualification.............................................2

2.2 Capitalization.............................................................2

2.3 Authorization of Transaction...............................................2

2.4 Offerees...................................................................2

2.5 Registration Right.........................................................2

2.6 Compliance with Securities and Exchange Commission Requirements............3

2.7 Brokerage..................................................................3


ARTICLE 3.  REPRESENTATIONS AND WARRANTIES OF INVESTOR.........................3

3.1 Investment Intent; Accredited Investor; Legends............................3

3.2 Authorization..............................................................4

3.3 Restricted Securities......................................................4

3.4 Brokerage..................................................................4


ARTICLE 4.  CONDITIONS OF INVESTOR'S OBLIGATIONS...............................4

4.1 Representations and Warranties.............................................4

4.2 Performance................................................................4

4.3 Consents and Waivers.......................................................5

4.4 Legal Action...............................................................5


ARTICLE 5.  AFFIRMATIVE COVENANTS OF THE COMPANY...............................5


<PAGE>

5.1 Use of Proceeds............................................................5

5.2 Board of Directors.........................................................5

5.3 Future Commissions.........................................................5

5.4 S-3 Registration...........................................................6


ARTICLE 6.  REGISTRATION; PUT OPTION...........................................6

6.1 S-3Registration............................................................6

6.2 Expenses...................................................................7

6.3 Indemnification............................................................7

6.4 Payment of Warrant Exercise Price; Refund of Warrant Exercise Proceeds.....9

6.5 Exclusive Obligation to Register...........................................9

6.6 Put Option.................................................................9


ARTICLE 7.  MISCELLANEOUS.....................................................10

7.1 Termination...............................................................10

7.2 Survival of Representations and Covenants.................................11

7.3 Notices...................................................................11

7.4 Publicity and Disclosures; Confidentiality................................12

7.5 Assignment................................................................12

7.6 Entire Agreement..........................................................12

7.7 Amendments and Waivers....................................................12

7.9 Counterparts..............................................................12

7.10 Effect of Table of Contents and Headings.................................12

SIGNATURES
LIST OF EXHIBITS

<PAGE>

                           WARRANT PURCHASE AGREEMENT
                           --------------------------

                         500,000 STOCK PURCHASE WARRANTS


         PURCHASE  AGREEMENT entered into as of the 18th day of August,  1999 by
and among Boston Biomedica, Inc., a Massachusetts corporation with its principal
place of business  at 375 West  Street,  West  Bridgewater,  Massachusetts  (the
"Company"),  and Paradigm Group,  L.L.C.,  an Illinois limited liability company
with its principal place of business at 3000 Dundee Road, Suite 105, Northbrook,
Illinois 60062 (the "Investor").

         WHEREAS, the Company desires to raise additional capital; and

         WHEREAS, the Investors are interested in investing in the Company;

         NOW,  THEREFORE,  in consideration of the mutual  agreements  contained
herein  and  for  other  good  and  valuable  consideration,   the  receipt  and
sufficiency  of which are  hereby  acknowledged,  the  parties  hereto  agree as
follows:

ARTICLE 1. DESCRIPTION OF PROPOSED FINANCING

         1.1  Authorization  of  Warrants.  The Company has  authorized  or will
              ---------------------------
authorize the issuance of: (i) nontransferable  stock purchase warrants dated as
of the  Closing  (hereinafter  defined)  and  evidencing  rights to  purchase an
aggregate of 400,000  shares of the Company's  common stock,  $.01 par value per
share  (the  "Common  Stock"),  at an  exercise  price  of  $4.25  per  share in
substantially the form of Exhibit A attached hereto (the "$4.25 Warrants");  and
                          ---------
(ii)  nontransferable  stock  purchase  warrants  dated  as of the  Closing  and
evidencing  rights to purchase an aggregate of 100,000  shares of the  Company's
Common Stock at an exercise price of $5.25 per share in  substantially  the form
of Exhibit B attached hereto (the "$5.25  Warrants") (the $4.25 Warrants and the
   ---------
$5.25  Warrants  are  collectively  referred to herein as the  "Warrants").  The
Warrants  shall  expire six  months  after the  Closing  as  defined  below (the
"Warrant Expiration Date").

         1.2 Purchase and Sale of Warrants.  Subject to the terms and conditions
             -----------------------------
of this  Agreement  and in  reliance  upon the  representations  and  warranties
contained  herein,  the Investor  agrees to purchase  from the Company,  and the
Company  agrees to sell to the  Investor,  at the  Closing,  the  Warrants at an
aggregate purchase price of $50,000 (the "Purchase Price").

         1.3  Closing.  The  Closing of the  purchase  and sale of the  Warrants
              -------
contemplated  by this Agreement  (herein the "Closing")  shall take place at the
offices of Brown,  Rudnick,  Freed & Gesmer,  One Financial  Center,  Boston, MA
02111 at 10:00 a.m. on the date of Closing  which shall be August 18, 1999 or at
such other time and place as shall be mutually  agreed by the  Investors and the
Company. At the Closing,  the Company shall deliver to the Investor the

<PAGE>

Warrants to be issued in the  Investor's  name  against  payment of the Purchase
Price therefor by wire transfer of immediately available funds.

ARTICLE 2. REPRESENTATIONS AND WARRANTIES OF THE COMPANY
--------------------------------------------------------

         The Company hereby represents and warrants to the Investor that:

         2.1  Organization  and  Qualification.  The  Company  is a  corporation
              --------------------------------
organized,  validly  existing  and  in  good  standing  under  the  laws  of the
Commonwealth of Massachusetts and has all required corporate power and authority
to own its property,  to carry on its business as presently  conducted and as it
presently  intends to conduct it and to carry out the transactions  contemplated
hereby.  The copies of the Articles of Incorporation and By-Laws of the Company,
as amended to date, which have been furnished to counsel for the Investor by the
Company are correct and complete.

         2.2  Capitalization.  The  authorized  capital  stock  of  the  Company
              --------------
consists  of  20,000,000  shares  of  Common  Stock,  $.01 par  value,  of which
4,770,153   shares  are  validly   issued  and   outstanding,   fully  paid  and
nonassessable,  and 1,000,000 shares of Preferred Stock, $.01 par value, none of
which shares are issued and  outstanding.  The Company has duly  authorized  and
reserved for issuance upon exercise of the Warrants a total of 500,000 shares of
Common  Stock (the  "Shares"),  and the Shares of Common  Stock issued upon such
exercise will be validly issued and outstanding, fully paid and nonassessable.

         2.3   Authorization  of  Transaction.   The  execution,   delivery  and
               ------------------------------
performance  of this  Agreement  have  been  duly  authorized  by all  necessary
corporate  or other  action  of the  Company  and it is the  valid  and  binding
obligation of the Company,  enforceable in accordance with its terms, subject to
general  principles  of equity and to laws of general  application  relating  to
bankruptcy,  insolvency  and the relief of debtors.  The  issuance of the Shares
upon exercise of the Warrants  pursuant to the terms of this Agreement  shall be
duly and  validly  authorized,  and no  further  approval  or  authority  of the
stockholders  or the  directors of the Company will be required for the issuance
and sale of the Shares as contemplated by this Agreement.

         2.4  Offerees.  Neither the Company nor anyone acting on its behalf has
              --------
within the past six (6) months  offered the  Warrants  for sale to, or solicited
any  offers to buy the same  from,  any  person or  organization  other than the
Investor  so as to bring the  offer,  issuance  or sale of the  Warrants  or the
issuance of Common Stock upon exercise of the Warrants,  as contemplated by this
Agreement,  within the provisions of Section 5 of the Securities Act of 1933, as
amended (the "Act").  Neither the Company nor anyone acting on its behalf has in
the past or will hereafter sell,  offer for sale or solicit offers to buy any of
said securities so as to bring the offer,  issuance or sale of the Warrants,  or
the issuance of Common Stock upon exercise of the Warrants,  as  contemplated by
this  Agreement,  within the provisions of Section 5 of the Act. The Company has
complied and will comply with all applicable state securities laws in connection
with the issuance and sale of the Warrants.

         2.5 Registration  Rights.  Other than such  registration  rights as are
             --------------------
granted pursuant to ARTICLE 6 of this Agreement, except as set forth on Schedule
                                                                        --------
2.5 hereto, no stockholder,
---

<PAGE>

noteholder,  or any other holder of any security issued by the Company,  nor any
holder of rights to acquire  any  security  from the  Company,  has any right to
require  the  Company  to  file,  or to join the  Company  in the  filing  of, a
registration statement or notification under the Act.

         2.6 Compliance  with Securities and Exchange  Commission  Requirements.
             ------------------------------------------------------------------
The Company has filed all reports,  proxy statements,  forms and other documents
(collectively,  the  "SEC  Documents")  required  to be  filed  by it  with  the
Securities and Exchange  Commission (the  "Commission")  under the Act and under
the Securities  Exchange Act of 1934, as amended (the "Exchange Act"), and as of
their respective dates such SEC Documents (i) complied in all material  respects
with the  requirements  of the Act or the Exchange  Act, as the case may be, and
the rules and regulations of the Commission promulgated thereunder applicable to
such SEC  Documents,  and (ii) did not  contain  at the time of their  filing an
untrue statement of a material fact or omit to state a material fact required to
be stated therein or necessary in order to make the statements therein, in light
of the circumstances under which they were made, not misleading.

         2.7 Brokerage. Except as set forth on Schedule 2.7 hereto, there are no
             ---------                         ------------
valid claims for brokerage commissions, finder's fees or similar compensation in
connection  with the  transactions  contemplated  by this Agreement based on any
arrangement  or  agreement  made by or on behalf of the  Company and the Company
will indemnify and hold the Investor  harmless  against any liability or expense
to them arising out of such a claim.

ARTICLE 3. REPRESENTATIONS AND WARRANTIES OF INVESTOR
-----------------------------------------------------

         The Investor hereby represents and warrants to the Company that:

         3.1 Investment Intent;  Accredited  Investor;  Legends. The Investor is
             --------------------------------------------------
purchasing or acquiring the Warrants for its own account for  investment and not
with a present view to, or for sale in connection with, any distribution thereof
in violation of the Act. The Investor represents and warrants that the Investor:
(a) is experienced in the evaluation of businesses  similar to the Company,  (b)
has such  knowledge and  experience  in financial and business  matters as to be
capable of evaluating the merits and risks of an investment in the Company,  (c)
has the ability to bear the economic risks of an investment in the Company,  (d)
has been furnished with or has had access to such information as is specified in
subparagraph  (b)(2) of Rule 502  promulgated  under  the Act and has  carefully
reviewed and understood such information,  (e) has been afforded the opportunity
to ask  questions  of and to receive  answers from the Company and to obtain any
additional  information  necessary to make an informed  investment decision with
respect to an investment in the Company, and (f) is an "Accredited  Investor" as
such term is defined in subparagraph (a) of Rule 501 promulgated  under the Act.
The Investor hereby consents to the imposition of a legend substantially similar
to the following on each Warrant and, unless  registered  under the Act pursuant
to ARTICLE 6 hereof,  each  certificate  for Shares of Common  Stock issued upon
exercise of the Warrants,  and the Investor agrees to abide by the  restrictions
contained therein:

         [This Warrant has] [The shares  represented by this  certificate  have]
not been registered under the Securities Act of 1933, as amended (the "Act") and
may not be sold, transferred,

<PAGE>

pledged,  hypothecated or assigned unless registered under the Act or an opinion
of counsel, satisfactory to the corporation, is obtained to the effect that such
sale, transfer or assignment is exempt from the registration requirements of the
Act.

         The  Investor  acknowledges  that  unless  the  Shares of Common  Stock
issuable  upon  exercise  of the  Warrants  have been  registered  under the Act
pursuant  to ARTICLE 6 hereof,  each  representation  and  warranty  made by the
Investor in this Section 3.1 must be made by the  Investor  again at the time of
each  exercise  of the  Warrants,  and the  exercise  of the  Warrants  shall be
conditioned and subject to such representation and warranty.

         3.2  Authorization.  The Investor has the power and  authority to enter
              -------------
into this Agreement and to perform all of its obligations hereunder.

         3.3 Restricted  Securities.  The Investor understands that the Warrants
             ----------------------
have not been  registered  under the Act by reason of a specific  exemption from
the  registration  provisions of the Act which depends upon, among other things,
the bona fide nature of the Investor's  investment  intent as expressed  herein.
The Investor acknowledges that the Warrants and, unless registered under the Act
pursuant to ARTICLE 6 hereof,  the Shares of Common Stock issuable upon exercise
of the  Warrants,  when  received,  must be held  indefinitely  unless  they are
subsequently  registered under the Act or an exemption from such registration is
available.  The Investor has been  advised of or is aware of the  provisions  of
Rule 144  promulgated  under  the Act,  which  rule  permits  limited  resale of
securities  purchased  in a private  placement  subject to the  satisfaction  of
certain conditions contained therein.

         3.4  Brokerage.  There are no valid claims for  brokerage  commissions,
              ---------
finder's  fees or  similar  compensation  in  connection  with the  transactions
contemplated  by this Agreement  based upon any arrangement or agreement made by
or on behalf of the  Investor  and the  Investor  agrees to  indemnify  and hold
harmless the Company  against any liability or expense to it arising out of such
a claim to the extent that such claim  arises out of actions or alleged  actions
of such Investor.

ARTICLE 4. CONDITIONS OF INVESTOR'S OBLIGATIONS
-----------------------------------------------

         The  obligation of the Investor to purchase and pay for the Warrants of
the Company  subscribed  for by the Investor at the Closing  shall be subject to
the satisfaction of each of the following conditions:

         4.1 Representations and Warranties.  The representations and warranties
             ------------------------------
of the Company  contained  herein or in the exhibits annexed hereto or otherwise
made  in  writing  by or on  behalf  of  the  Company  in  connection  with  the
transactions  contemplated  hereby  shall be true and  correct as of the Closing
with the same effect as though made on and as of that date.

         4.2 Performance. The Company shall have performed and complied with all
             -----------
of the agreements and conditions  contained  herein and required to be performed
or  complied  with by the Company at or prior to the Closing and shall not be in
breach of any provision of this Agreement.

<PAGE>

         4.3 Consents and Waivers. All necessary consents,  waivers,  approvals,
             --------------------
amendments  and other  action on the part of any person  necessary  to have been
obtained or effected in order to carry out the transactions contemplated by this
Agreement  shall have been duly  obtained or effected and shall be in full force
and effect and adequate.

         4.4 Legal Action.
             ------------

         (a)......There  shall  not  have  been  instituted  or  threatened  any
material  legal   proceeding   seeking  to  prohibit  the  consummation  of  the
transactions  contemplated  by this  Agreement,  or to obtain  damages  from the
Investor with respect thereto.

         (b)......None  of the parties  hereto shall be prohibited by any order,
writ,  injunction or decree of any governmental  body of competent  jurisdiction
from consummating the transactions contemplated by this Agreement, and no action
or  proceeding  shall then be  pending  which  questions  the  validity  of this
Agreement,  any of the transactions  contemplated hereby or any action which has
been taken by any of the parties in connection  herewith or in  connection  with
any of the transactions contemplated hereby.

ARTICLE 5. AFFIRMATIVE COVENANTS OF THE COMPANY
-----------------------------------------------

         The Company covenants with the Investor that:

         5.1 Use of Proceeds.  The Company  shall use the proceeds from the sale
             ---------------
of the Warrants to the Investor and the exercise of the Warrants by the Investor
for general  working  capital  purposes  and not for the  repayment  of existing
indebtedness or other obligations to any insider of the Company.

         5.2 Board of  Directors.  The Company  agrees that within ten  business
             -------------------
days following the exercise,  in the  aggregate,  of 90% of the Warrants and the
payment of the  exercise  price  therefor  and  issuance  of, in the  aggregate,
450,000 Shares in respect thereof, the Company shall cause Sheldon Drobny or his
designee to be appointed to the board of directors of the Company.

         5.3 Future Commissions. Subject to the requirements of applicable state
             ------------------
and  federal  securities  laws,  the  Company  shall pay to the  Investor or its
designee  a three  percent  (3%)  commission  on any and all  amounts  received,
directly  or  indirectly,  by  the  Company  or  any  of  its  affiliates,  as a
consequence of any merger,  license or other similar arrangement or remuneration
which  results as a direct  consequence  of the  efforts of the  Investor or its
identified  designee or agent,  provided  however that such commission  shall be
payable  hereunder  only if the Company's  senior  management  has approved,  in
writing and prior to any contact by the Investor with any person or entity, such
efforts of the  Investor or its  identified  designee or agent.  As used in this
Section 5.3, the term  "affiliates"  shall include the principals and associates
of the Company and any individual, corporation, organization, firm or company of
which the Company is a member,  employee,  principal, or party to, or from which
the Company would otherwise benefit financially, either directly or indirectly.


<PAGE>

         5.4 S-3 Registration. The Company shall use its best efforts to prepare
             ----------------
and file with the Commission a  registration  statement on Form S-3 with respect
to the Shares (the  "Registration  Statement") within thirty (30) days following
the Closing pursuant to ARTICLE 6 hereof. The Company shall use its best efforts
to cause such Registration Statement to become effective within ninety (90) days
following the Closing and remain  effective for such period as may be reasonably
necessary  to effect  the sale of such  Shares,  not to exceed  nine (9)  months
following the Closing.


ARTICLE 6. REGISTRATION; PUT OPTION
-----------------------------------

         6.1 S-3 Registration. The Company shall use its best efforts to:
             ----------------

         (a)......prepare  and file with the Commission  within thirty (30) days
following the Closing a Registration  Statement with respect to the Shares,  and
use its best efforts to cause such  Registration  Statement to become and remain
effective for such period as may be  reasonably  necessary to effect the sale of
such Shares, not to exceed nine (9) months;

         (b)......prepare  and file with the Commission  such amendments to such
Registration  Statement and supplements to the prospectus  contained  therein as
may be necessary to keep such Registration  Statement  effective for such period
as may be reasonably  necessary to effect the sale of such Shares, not to exceed
nine (9) months;

         (c)......furnish to the Investor participating in such registration and
to the underwriters of the securities being registered,  if any, such reasonable
number of copies of the Registration Statement,  preliminary  prospectus,  final
prospectus and such other documents as such underwriters may reasonably  request
in order to facilitate the public offering of such securities;

         (d)......use  its best  efforts to register  or qualify the  securities
covered by such  Registration  Statement under the state  securities or blue sky
laws of such  jurisdictions as the Investor may reasonably request within twenty
(20) days following the original filing of such Registration  Statement,  except
that the  Company  shall not for any  purpose be  required  to execute a general
consent  to  service  of  process  or to  qualify  to do  business  as a foreign
corporation in any jurisdiction wherein it is not so qualified;

         (e)......notify  the Investor,  promptly  after it shall receive notice
thereof, of the time when such Registration  Statement has become effective or a
supplement to any prospectus  forming a part of such Registration  Statement has
been filed;

         (f)......notify  the Investor promptly of any request by the Commission
for the amending or supplementing of such  Registration  Statement or prospectus
or for additional information;

         (g)......prepare  and  file  with  the  Commission,  promptly  upon the
request of the Investor,  any  amendments or  supplements  to such  Registration
Statement or prospectus which, in

<PAGE>

the opinion of counsel for the  Investor  (and  concurred  in by counsel for the
Company),  is required under the Act or the rules and regulations  thereunder in
connection with the distribution of the Registrable Securities by such Investor;

         (h)......prepare  and promptly  file with the  Commission  and promptly
notify  the  Investor  of the filing of such  amendment  or  supplement  to such
Registration  Statement  or  prospectus  as  may be  necessary  to  correct  any
statements  or  omissions  if, at the time when a  prospectus  relating  to such
securities  is  required  to be  delivered  under the Act,  any event shall have
occurred as the result of which any such  prospectus or any other  prospectus as
then in effect would  include an untrue  statement of a material fact or omit to
state any material fact necessary to make the statements  therein,  in the light
of the circumstances in which they were made, not misleading; and

         (i)......advise the Investor, promptly after it shall receive notice or
obtain  knowledge  thereof,  of the issuance of any stop order by the Commission
suspending the effectiveness of such Registration Statement or the initiation or
threatening of any proceeding for that purpose and promptly use its best efforts
to prevent the  issuance of any stop order or to obtain its  withdrawal  if such
stop order should be issued.

         6.2 Expenses.  All fees,  costs and expenses of and  incidental to such
             --------
registration,  inclusion  and public  offering (as  specified  in paragraph  (b)
below) in  connection  therewith  shall be borne by the Company,  other than the
fees and costs of counsel to the  Investor,  which fees and costs shall be borne
by the Investor; and provided,  however, that any security holders participating
in such  registration  shall bear  their pro rata share of (i) the  underwriting
discount and commissions and transfer taxes, and (ii) the expense of any special
audit of the Company's financial  statements if the registration does not permit
use of existing or contemplated audited statements.

         6.3 Indemnification.
             ---------------

         (a)......The  Company  will  indemnify  and hold  harmless the Investor
whose Shares are included in a Registration Statement pursuant to the provisions
of this Article and any  underwriter  (as defined in the Act) for such  Investor
and each person,  if any, who controls such Investor or such underwriter  within
the meaning of the Act, from and against,  and will  reimburse such Investor and
each such underwriter and controlling  person with respect to, any and all loss,
damage,  liability,  cost  and  expense  to  which  such  Investor  or any  such
underwriter or controlling person may become subject under the Act or otherwise,
insofar as such losses,  damages,  liabilities,  costs or expenses are caused by
any untrue  statement or alleged untrue statement of any material fact contained
in  such  Registration  Statement,  any  prospectus  contained  therein  or  any
amendment or supplement  thereto, or arise out of or are based upon the omission
or alleged  omission  to state  therein a material  fact  required  to be stated
therein  or  necessary  to  make  the  statements   therein,  in  light  of  the
circumstances in which they were made, not misleading;  provided,  however, that
the  Company  will not be liable in any such  case to the  extent  that any such
loss,  damage,  liability,  cost or  expense  arises  out of or is based upon an
untrue  statement or alleged untrue statement or omission or alleged omission so
made in conformity with

<PAGE>
information  furnished by such Investor,  such  underwriter or such  controlling
person in writing specifically for use in the preparation thereof.

         (b)......The  Investor  whose  Shares are  included  in a  Registration
Statement  pursuant to the  provisions  of this Article will  indemnify and hold
harmless the Company,  any underwriter and any controlling person of the Company
or  such  underwriter  from  and  against,   and  will  reimburse  the  Company,
underwriter  or  controlling  person with respect to, any and all loss,  damage,
liability,  cost or  expense  to  which  the  Company,  any  underwriter  or any
controlling  person  thereof  may  become  subject  under the Act or  otherwise,
insofar as such losses,  damages,  liabilities,  costs or expenses are caused by
any untrue or alleged  untrue  statement of any material fact  contained in such
Registration  Statement,  any prospectus  contained  therein or any amendment or
supplement  thereto,  or arise  out of or are  based  upon the  omission  or the
alleged  omission to state therein a material fact required to be stated therein
or necessary to make the statements  therein,  in light of the  circumstances in
which they were made, not  misleading,  in each case to the extent,  but only to
the extent,  that such untrue  statement or alleged untrue statement or omission
or alleged  omission was so made in reliance upon and in strict  conformity with
written  information  furnished  by such  Investor  specifically  for use in the
preparation thereof.

         (c)......Promptly after receipt by an indemnified party pursuant to the
provisions  of  paragraph  (a) or (b)  of  this  Section  6.3 of  notice  of the
commencement  of any  action  involving  the  subject  matter  of the  foregoing
indemnity  provisions,  such indemnified party will, if a claim thereof is to be
made against the indemnifying  party pursuant to the provisions of paragraph (a)
or (b), promptly notify the indemnifying party of the commencement  thereof; but
the  omission to so notify the  indemnifying  party will not relieve it from any
liability which it may have to any  indemnified  party otherwise than hereunder.
In case such action is brought against any indemnified party and it notifies the
indemnifying  party of the commencement  thereof,  the indemnifying  party shall
have the right to participate  in, and, to the extent that it may wish,  jointly
with any other  indemnifying  party  similarly  notified,  to assume the defense
thereof, with counsel satisfactory to such indemnified party; provided, however,
that if the defendants in any action include both the indemnified  party and the
indemnifying  party and the indemnified  party shall have  reasonably  concluded
that  there  may be legal  defenses  available  to it and/or  other  indemnified
parties  which  are  different  from or  additional  to those  available  to the
indemnifying  party,  or if there is a conflict of interest  which would prevent
counsel for the indemnifying party from also representing the indemnified party,
the indemnified party or parties shall have the right to select separate counsel
to participate in the defense of such action on behalf of such indemnified party
or parties. After notice from the indemnifying party to the indemnified party of
its election so to assume the defense of any action, the indemnifying party will
not be liable to such indemnified party pursuant to the provisions of paragraphs
(a) or (b) hereof for any legal or other expense  subsequently  incurred by such
indemnified  party in connection  with the defense thereof other than reasonable
costs of  investigation,  unless (i) the  indemnified  party shall have employed
counsel in accordance  with the provision of the  preceding  sentence,  (ii) the
indemnifying  party  shall  not  have  employed  counsel   satisfactory  to  the
indemnified  party to represent the  indemnified  party within a reasonable time
after the notice of the commencement of


<PAGE>
the action,  or (iii) the  indemnifying  party has  authorized the employment of
counsel for the indemnified party at the expense of the indemnifying party.

         6.4  Payment  of Warrant  Exercise  Price;  Refund of Warrant  Exercise
              ------------------------------------------------------------------
Proceeds.
---------

         (a)......If at the time of exercise of any Warrants by the Investor the
Commission  has not  declared the  Registration  Statement  effective,  then the
Investor shall reaffirm in writing the  representations and warranties set forth
in Section 3.1 hereof,  and at the Investor's  election the Investor may either:
(i) make payment of the exercise  price of such Warrants to the Company  against
delivery of  unregistered  Shares  subject to the  restrictions  of and with the
legend set forth in Section 3.1; or (ii) delay  payment of the  exercise  price,
without  accrual  of  interest  thereon,  until  the  business  day  immediately
following the date the Investor receives notice that the Commission has declared
the Registration Statement effective.  In the event the Investor elects to delay
such payment,  certificates  representing the Shares issuable in connection with
such exercise shall be delivered to the Investor when the Registration Statement
has become effective and such payment has been received by the Company.

         (b)......If the Commission has not declared the Registration  Statement
effective by the close of business on the  ninetieth  (90th) day  following  the
Closing, the Company shall refund to the Investor an amount equal to one percent
(1%) of the combined  proceeds of the exercise of the Warrants  theretofore paid
to  the  Company.  Thereafter,  following  the  completion  of  each  successive
thirty-day  period during which the Commission has not declared the Registration
Statement effective, the Company shall refund to the Investor an amount equal to
an additional  one percent (1%) of the combined  proceeds of the exercise of the
Warrants theretofore paid to the Company. In the event of any refund pursuant to
this Section (b), the Warrants  theretofore  exercised  shall be  considered  as
having  been  exercised  in  full  as  of  their  original  exercise  date  at a
proportionately  reduced  exercise price. If the Commission has not declared the
Registration  Statement effective because of any action or failure to act by the
Investor,  there  shall be no  refund of the  proceeds  of the  exercise  of the
Warrants under this Section (b).

         6.5  Exclusive  Obligation  to  Register.  Except as  provided  in this
              -----------------------------------
ARTICLE 6 and in Section 5.4 hereof,  the Company will have no obligation to the
Investor to register under the Act any Shares received by the Investor  pursuant
to this Agreement.

         6.6 Put Option. If at any time or times following the effective date of
             ----------
the Registration Statement and prior to the Warrant Expiration Date during which
the Registration Statement remains effective,  both the closing bid price of the
Company's  Common  Stock,  as reported on the Nasdaq  National  Market,  and the
average  closing bid price of the Company's  Common Stock over the fourteen (14)
trading days immediately prior thereto (together,  the "15 Trading Day Period"),
equals or exceeds $6.75 (the "(Price Condition"); then the Company shall at each
such time or at any time  thereafter  have the option (a "Put Option") to compel
the Investor to exercise the Warrants as  hereinafter  provided and make payment
to the Company of the aggregate  exercise  price  therefor by providing  written
notice to the  Investor of the  Company's  election to exercise  the Put Option.
Within ten (10) business days following the date of each such notice


<PAGE>
(each such notice date referred to herein as a "Put Option Election Date"),  the
Investor shall exercise the Warrants with respect to that number of Shares as is
equal to the lesser of:

                                    (A)      500,000, less such number of Shares
                                             as  to  which  Warrants  have  been
                                             previously    exercised,     either
                                             pursuant  to  the  exercise  of  an
                                             earlier  Put Option or  pursuant to
                                             an earlier  exercise of Warrants by
                                             the Investor;

                                    (B)      the number of Shares  specified  by
                                             the Company in each such notice; or

                                    (C)      unless the Aggregate Trading Volume
                                             Condition (defined below) is met, a
                                             quotient, the numerator of which is
                                             equal  to the  product  of  500,000
                                             times  the  average  daily  trading
                                             volume  of  the  Company's   Common
                                             Stock  for  the  15   Trading   Day
                                             Period,   and  the  denominator  of
                                             which is equal 40,000.

In the event the Price  Condition is met and the  aggregate  number of shares of
the Company's  Common Stock traded on the Nasdaq National Market exceeds 300,000
shares  during any 30 trading day period  prior to the Warrant  Expiration  Date
(the "Aggregate Trading Volume Condition"), then following written notice of the
Company's  election to exercise the Put Option,  the Investor shall exercise the
Warrants  with respect to that number of Shares as is equal to the lesser of (A)
or (B) above.  In the event the Investor fails to exercise the Warrants and make
payment to the Company of the aggregate  exercise price therefor within ten (10)
business  days  following  the Put Option  Election  Date,  the Company  may, in
addition to any other  remedies it may have under this  Agreement or  otherwise,
terminate  the  Warrants  without  any  obligation  to obtain the  consent of or
provide notice to the Investor,  or deem the Warrants to have been exercised and
demand payment of the exercise price therefor.


ARTICLE 7. MISCELLANEOUS
------------------------

         7.1 Termination.
             -----------

         (a) At any time prior to the Closing,  this Agreement may be terminated
(i) by mutual  consent of the  parties,  (ii) by either side if there has been a
material  misrepresentation,  breach of  warranty  or breach of  covenant by the
other side in its  representations,  warranties  and covenants set forth herein,
(iii) by the  Investor  if the  conditions  stated  in  ARTICLE  4 have not been
satisfied at or prior to the Closing.

         (b) If this  Agreement  shall be  terminated  in  accordance  with this
Section 7.1, all obligations of the parties  hereunder  shall terminate  without
liability  of any party to the others  except as provided in Section 7.4. In the
event that this Agreement is so  terminated,  each party will return all papers,
documents, financial statements and other data furnished to it by or with

<PAGE>

respect to each other party to such other party  (including  any copies  thereof
made by the first party).

         (c) This Agreement shall terminate  without further liability to any of
the  parties at such time as all of the  obligations  of the  Company  under the
Warrants have been fully satisfied and discharged.

         7.2 Survival of  Representations  and Covenants.  All  representations,
             -------------------------------------------
warranties,  covenants,  agreements  and  obligations  made  herein  or  in  any
schedule,  exhibit, notice, certificate or other document executed in connection
herewith or delivered  by any party to another  party  incident  hereto shall be
deemed to have been  relied  upon by the other  party  hereto  and  survive  the
execution  and/or  delivery  thereof,  and all statements  contained in any such
schedules, exhibit, notice, certificate or other document delivered hereunder or
in  connection  herewith  shall be  deemed  to  constitute  representations  and
warranties made by the parties herein.

         7.3 Notices.  Any notice or other communication in connection with this
             -------
Agreement  shall be deemed to be  delivered  if in writing  (or in the form of a
telegram)  addressed as provided  below and if either (a) actually  delivered at
said  address,  or (b) in the case of a letter,  three  business days shall have
elapsed  after the same shall have been  deposited in the United  States  mails,
postage prepaid and registered or certified, return receipt requested:

         If to the Company, to:

                           Boston Biomedica, Inc.
                           375 West Street
                           West Bridgewater, MA  02379
                           Attn:  Richard T. Schumacher, President

         with a copy to:

                           Brown, Rudnick, Freed & Gesmer, P.C.
                           One Financial Center
                           Boston, MA  02111
                           Attn:  Steven R. London, Esq.
                           Fax:  (617) 856-8201


         If to the Investors, to:

                           Paradigm Group, L.L.C.
                           3000 Dundee Road
                           Suite 105
                           Northbrook, IL  60062



<PAGE>

and in any case at such other address as the addressee  shall have  specified by
written  notice.  All  periods  of  notice  shall be  measured  from the date of
delivery thereof.

         7.4 Publicity and  Disclosures;  Confidentiality.  No press releases or
             --------------------------------------------
any public disclosure,  either written or oral, of the transactions contemplated
by this Agreement  shall be made without the prior knowledge and written consent
of the  Company.  The  Investor  agrees that it will keep  confidential  and not
disclose or divulge any confidential, proprietary or secret information which it
may obtain from the Company in  connection  with the  transactions  contemplated
herein,   or  pursuant  to  inspection  rights  granted  hereunder  unless  such
information is or hereafter becomes public information.

         7.5  Assignment.  This Agreement and the rights  hereunder shall not be
              ----------
assignable by either party.

         7.6  Entire  Agreement.  This  Agreement  (including  all  exhibits  or
              -----------------
schedules appended to this Agreement and all documents  delivered pursuant to or
referred to in this Agreement,  all of which are hereby  incorporated  herein by
reference)  constitutes  the  entire  agreement  between  the  parties,  and all
promises,  representations,   understandings,  warranties  and  agreements  with
reference to the subject  matter  hereof and  inducements  to the making of this
Agreement relied upon by any party hereto,  have been expressed herein or in the
documents incorporated herein by reference.

         7.7 Amendments  and Waivers.  Changes in or additions to this Agreement
             -----------------------
may be made or  compliance  with any term,  covenant,  agreement,  condition  or
provision set forth herein or therein may be omitted or waived (either generally
or in a particular  instance and either  retroactively or  prospectively),  only
upon written consent of the Company and the Investor.

         7.8  Governing  Law;  Severability.  This  Agreement  shall be deemed a
              -----------------------------
contract made under the laws of the Commonwealth of Massachusetts  and, together
with the rights and  obligations  of the parties  hereunder,  shall be construed
under  and  governed  by the  laws  of  such  Commonwealth.  The  invalidity  or
unenforceability  of any  provision  of this  Agreement  shall  not  affect  the
validity or enforceability of any other provision hereof.

         7.9   Counterparts.   This   Agreement  may  be  executed  in  multiple
               ------------
counterparts,  each of  which  shall  be  deemed  in  original  but all of which
together shall constitute one and the same instrument.

         7.10 Effect of Table of Contents and  Headings.  Any table of contents,
              -----------------------------------------
title of an article or section  heading herein  contained is for  convenience of
reference  only and shall not affect the meaning of  construction  of any of the
provisions hereof.


         IN  WITNESS  WHEREOF,  this  Agreement  has been  executed  as a sealed
instrument  by the  parties  hereto  or their  duly  authorized  representatives
effective as of the date first above written.


<PAGE>

                                                  BOSTON BIOMEDICA, INC.


Corporate Seal
                                                  By: /S/ Richard T. Schumacher
                                                     --------------------------

ATTEST:

/S/ Nancy M. Snell
-----------------------------
Notary
Commission Expires  Sept 24, 2004




                                                     PARADIGM GROUP, L.L.C.


                                                  By: /S/
                                                     --------------------------





                                LIST OF EXHIBITS
                                ----------------


A.       Form of $4.25 Stock Purchase Warrant

B.       Form of $5.25 Stock Purchase Warrant

C.       Disclosure Schedules



<PAGE>


                                    SCHEDULES


                                      -14-
<PAGE>


                                  Schedule 2.5

                               Registration Rights
                               -------------------

         The Company is a party to a Registration Rights Agreement dated June 5,
1990, as amended (the "Registration  Agreement"),  with G&G Diagnostics  Limited
Partnership I and G&G  Diagnostics  Limited  Partnership  II  (together,  "G&G")
pursuant  to which G&G has  certain  rights to have its  shares of Common  Stock
registered by the Company under the Securities Act. A total of 357,667 shares of
Common Stock (the "Registrable  Shares") held by G&G or subject to warrants held
by G&G may be  registered  under  the  Registration  Agreement.  If the  Company
proposes to register any of its securities  under the Securities Act, either for
its own account or for the account of other securityholders,  G&G is entitled to
notice of the registration and is entitled to include, at the Company's expense,
the  Registrable  Shares therein,  provided,  among other  conditions,  that the
underwriters  have the right to limit the number of such shares  included in the
registration. In addition, G&G may require the Company at its expense on no more
than two occasions,  to file a registration  statement  under the Securities Act
with respect to its Registrable  Shares,  and the Company is required to use its
best efforts to effect such a  registration,  subject to certain  conditions and
limitations. Further, G&G may require the Company at its expense to register the
Registrable  Shares  on Form S-3 when  such form is  available  to the  Company,
subject to certain conditions and limitations.


                                      -15-


<PAGE>



                                  Schedule 2.7

                                    Brokerage

         In  connection  with this  Agreement,  the  Company  will pay  National
Securities,  a registered  broker dealer, a fee equal to six percent (6%) of the
Purchase  Price paid by the  Investor and received by the Company at the Closing
and six percent (6%) of the  aggregate  amount paid by the Investor and received
by the Company upon exercise of the Warrants (net of any refunds  payable by the
Company  to the  Investor  subsequent  to the  exercise  of  the  Warrants).  In
addition,  the Company  will issue to National  Securities  warrants to purchase
shares of the Company's common stock as follows:

Warrants to Purchase Shares  Exercise Price      Restriction on Exercise
---------------------------  --------------      -----------------------

      40,000                   $4.25/share  Exercisable for that percentage of
                                            the 40,000 shares equal to that
                                            percentage of the Investor's $4.25
                                            Warrant for 400,000 shares which
                                            have been exercised by the Investor.

      10,000                   $5.25/share  Immediately exercisable in full.

      25,000                   $8.00/share  Only exercisable if and when the
                                            Investor has exercised in full its
                                            Warrants to purchase 500,000 shares.

         The warrants to be issued to National  Securities will expire on August
15, 2001.

                                      -16-