1. Name and Address of Reporting Person
   SHAUGHNESSY, DENNIS R.
   251 Ballardvale Street
   Wilmington, MA 01887
   USA
2. Issuer Name and Ticker or Trading Symbol
   Charles River Laboratories Int'l., Inc (CRL)
3. IRS or Social Security Number of Reporting Person (Voluntary)
4. Statement for Month/Year
   3/2003
5. If Amendment, Date of Original (Month/Day/Year)
6. Relationship of Reporting Person(s) to Issuer (Check all applicable)
   ( ) Director                   ( ) 10% Owner
   (X) Officer (give title below) ( ) Other (specify below)
   Sr. VP Corporate Development
7. Individual or Joint/Group Filing (Check Applicable Line)
   (X) Form filed by One Reporting Person
   ( ) Form filed by More than One Reporting Person

TABLE I -- Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
+---------------------------------+----------+-------------+-----------------------------+----------------+-----------+------------+ |1. Title of Security |2. Trans- |3. Trans- |4. Securities Acquired (A) |5. Amount of |6. Owner- |7. Nature | | | action | action | or Disposed of (D) | Securities | ship | of In- | | | Date | Code | | Beneficially | Form: | direct | | | | | | Owned at | Direct | Bene- | | | (Month/ | | | End of | (D) or | ficial | | | Day/ +-------+-----+-----------+------+----------+ Month | Indirect| Owner- | | | Year) |Code |V |Amount |A/D |Price | | (I) | ship | +---------------------------------+----------+-------+-----+-----------+------+----------+----------------+-----------+------------+ Common Stock 03/07/2003 M 5000 A $16.0000 20761 D
TABLE II -- Derivative Securities Acquired, Disposed of, or Beneficially Owned
+-------------+--------+----------+---------+-----------+---------------------+----------------+----------+--------+-------+-------+ |1. |2. |3. |4. |5. |6. |7. |8. |9. |10. |11. | | | | | | | | | |Number |Owner- | | | | | | | | | | |of |ship | | | | | | | | | | |Deriv- |Form of| | | | | | | | |Title and Amount| |ative |Deriv- | | | | | | | | |of Underlying | |Secur- |ative |Nature | | |Conver- | | |Number of | |Securities | |ities |Secur- |of | | |sion or | | |Derivative |Date Exercisable +-------+--------+ |Benefi- |ity: |In- | | |Exercise| | |Securities |and Expiration Date | |Amount | |cially |Direct |direct | | |Price of|Transac- |Transac- |Acquired(A)|(Month/Day/Year) | |or | |Owned |(D) or |Bene- | |Title of |Deriv- |tion Date |tion Code|Disposed(D)+----------+----------+ |Number |Price of |at End |In- |ficial | |Derivative |ative |(Month/ +------+--+-----+-----+Date Exer-|Expira- | |of |Derivative|of |direct |Owner- | |Security |Security|Day/Year) |Code |V |(A) |(D) |cisable |tion Date |Title |Shares |Security |Month |(I) |ship | +-------------+--------+----------+------+--+-----+-----+----------+----------+-------+--------+----------+--------+-------+-------+ Stock Options $16 03/07/2003 M 5000 06/23/2001 06/23/2010 Common 5000 $16.0000 11000 D (Right to buy) Stock Explanation of Responses:
SIGNATURE OF REPORTING PERSON /s/ DENNIS R. SHAUGHNESSY DATE 03/10/2003