EXHIBIT 32.1


                                CERTIFICATION (1)


Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (18 U.S.C. Section
1350, as adopted), Kevin P. Corcoran, Chief Executive Officer of Lynx
Therapeutics, Inc. (the "Company"), and Kathy A. San Roman, Vice President,
Human Resources & Administration and Acting Chief Financial Officer of the
Company, each hereby certifies that, to the best of his and her knowledge:

1.   The Company's Annual Report on Form 10-K for the period ended December 31,
     2003, to which this Certification is attached as Exhibit 32.1 (the
     "Periodic Report"), fully complies with the requirements of Section 13(a)
     or Section 15(d) of the Securities Exchange Act of 1934, as amended; and

2.   The information contained in the Annual Report fairly presents, in all
     material respects, the financial condition and the results of operations of
     the Company.

IN WITNESS WHEREOF, the undersigned have set their hands hereto as of March 30,
2004.


                                   /s/ Kevin P. Corcoran
                                   -----------------------------------------
                                   Kevin P. Corcoran
                                   Chief Executive Officer

                                   /s/ Kathy A. San Roman
                                   -----------------------------------------
                                   Kathy A. San Roman
                                   Vice President, Human Resources &
                                   Administration and
                                   Acting Chief Financial Officer

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(1)   This certification "accompanies" the Annual Report on Form 10-K to which
      it relates, pursuant to Section 906 of the Sarbanes Oxley Act of 2002, and
      is not deemed filed with the Securities and Exchange Commission and is not
      to be incorporated by reference into any filing of Lynx Therapeutics, Inc.
      under the Securities Act or the Exchange Act (whether made before or after
      the date of the Annual Report on Form 10-K), irrespective of any general
      incorporation language contained in such filing.