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At your request, we have examined the Registration Statement on Form S-8 (the “Registration Statement”) to be filed by Pacific Biosciences of California, Inc., a Delaware corporation (the “Company”), with the Securities and Exchange Commission (the “Commission”), on or about the date hereof, relating to the registration under the Securities Act of 1933, as amended (the “Act”), of 4,000,000 shares of your common stock, par value $0.001 per share (the “Shares”), to be issued under the Company’s 2010 Employee Stock Purchase Plan (the “2010 ESPP”). As your legal counsel, we have reviewed the actions proposed to be taken by you in connection with the issuance and sale of the Shares to be issued under the 2010 ESPP.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when issued and sold in the manner described in the 2010 ESPP and pursuant to the agreements that accompany the 2010 ESPP, will be legally and validly issued, fully paid and nonassessable.

We hereby consent to the filing of this opinion as an exhibit to the above-referenced Registration Statement and to the use of our name wherever it appears in the Registration Statement and in any amendments thereto. In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Act or the rules and regulations of the Commission thereunder.

AUSTIN BEIJING BOSTON BOULDER BRUSSELS HONG KONG LONDON LOS ANGELES NEW YORK PALO ALTO
SALT LAKE CITY SAN DIEGO SAN FRANCISCO SEATTLE SHANGHAI WASHINGTON, DC WILMINGTON, DE


			Wilson Sonsini Goodrich & Rosati Professional Corporation 650 Page Mill Road Palo Alto, California 94304-1050 o: 650.493.9300 f: 650.493.6811