EXHIBIT 10.56

AMENDMENT TO

EXECUTIVE EMPLOYMENT AND SEVERANCE AGREEMENT

      This amendment to the Executive Employment and Severance Agreement (the
“Agreement”) that was made effective as of December 5, 2002, by and between
Invitrogen Corporation (“Company”) and James R. Glynn (“Executive”) is entered
into by such parties as of June 27, 2003. All capitalized terms used herein
shall have the meaning ascribed thereto in the Agreement.

RECITALS

      A. Executive has been employed by the Company since December 5, 2002,
pursuant to the Agreement, and, except for this amendment, Executive’s
employment would terminate on June 29, 2003.

      B. The parties wish to extend Executive’s employment under the Agreement
until July 31, 2003.

      The parties agree as follows:

        1. A Triggering Event pursuant to Section 9.2(b) of the Agreement shall
have occurred on June 29, 2003, thereby entitling the Executive to receive the
Consulting and Severance Package.           2. Section 12 of the Agreement is
hereby revised to read in its entirety as follows:

        12. Date of Termination. “Date of Termination” means the first to occur
of:

        12.1 July 31, 2003; or           12.2 the date of receipt of the Notice
of Termination (i.e., termination for Good Reason) or any later date specified
therein, as the case may be; or           12.3 Executive’s death; or          
12.3 the effective date of Executive’s Disability.

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        2.     All other provisions of the Agreement shall remain in full force
and effect.

             
Dated:
  6/21/03

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  /s/ JAMES R. GLYNN

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JAMES R. GLYNN  
Dated:
  6/27/03

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  /s/ LEWIS J. RUNCHEY

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INVITROGEN CORPORATION
Lewis J. Runchey
Vice President, Human Resources