FORM OF SUBSCRIPTION AGREEMENT

Exhibit 10.2

FORM OF

SUBSCRIPTION AGREEMENT

January 29, 2009

Pharmasset, Inc.

303-A College Road East

Princeton, NJ 08540

Ladies and Gentlemen:

The undersigned (the “ Investor ”), hereby confirms and agrees with you as follows:

1. This Subscription Agreement (the “ Agreement ”) is made as of the date hereof between Pharmasset, Inc., a Delaware corporation (the “ Company ”), and the Investor.

2. The Company has authorized the sale and issuance to certain investors of up to an aggregate of 4,678,000 shares (the “ Shares ”) of its Common Stock, par value $0.001 per share (the “ Common Stock ”), for a purchase price of $9.73 per share (the “ Purchase Price ”). All defined terms used herein and not otherwise defined shall have the same meanings ascribed to such terms in the Placement Agency Agreement dated the date hereof by and between Leerink Swann LLC (the “ Placement Agent ”) and the Company (the “ Placement Agency Agreement ”).

3. The offering and sale of the Shares (the “ Offering ”) are being made pursuant to (1) an effective Registration Statement on Form S-3 (Registration No. 333-151749) (the “ Registration Statement ”) filed by the Company with the Securities and Exchange Commission (the “ SEC ”), which contains the base prospectus (the “ Base Prospectus ”) and was declared effective by the SEC on June 26, 2008, (2) if applicable, each “free writing prospectus” (as that term is defined in Rule 405 under the Securities Act of 1933, as amended), that has been or will be provided to the Investor on or prior to the date hereof and (3) a final prospectus supplement (the “ Prospectus Supplement ” and together with the Base Prospectus, the “ Prospectus ”) containing certain supplemental information regarding the Shares and terms of the Offering that will be filed with the SEC and provided to the Investor along with the Company’s counterpart to this Agreement or made available to the Investor by the filing by the Company of an electronic version thereof with the SEC. The Registration Statement, the documents incorporated by reference therein and all free writing prospectuses are referred to herein collectively as the “ Disclosure Package. ”

4. The Company and the Investor agree that the Investor will purchase from the Company, and the Company will issue and sell to the Investor, the number of Shares set forth below for the aggregate purchase price set forth below, pursuant to and subject to the Terms and Conditions for Purchase of Shares attached hereto as Annex I , which are incorporated herein by reference as if fully set forth herein. Unless otherwise requested by the Investor no later than one business day after the execution of this Agreement by the Investor and agreed to by the Company, the Shares purchased by the Investor will be delivered by electronic book-entry at The Depository Trust Company (“ DTC ”), registered in the Investor’s name and address as set forth below and will be released by

Computershare, the Company’s transfer agent (the “ Transfer Agent ”), to the Investor at the Closing (as defined in the Terms and Conditions for Purchase of Shares). The Investor acknowledges that the Offering is not being underwritten by the Placement Agent and that there is no minimum offering amount. The Investor understands and agrees that the Company, in its sole discretion, reserves the right to accept or reject this subscription for Shares, in whole or in part.

5. The Investor represents that, except as set forth below, (a) it has had no position, office or other material relationship within the past three years with the Company or persons known to it to be affiliates of the Company, (b) it is not, and as of the Closing will not be, a member of FINRA or an Associated Person (as such term is defined under the NASD Membership and Registration Rules Section 1011), and (c) neither the Investor nor any group of Investors (as identified in a public filing made with the SEC) of which the Investor is a part in connection with the Offering of the Shares, acquired, or obtained the right to acquire, 20% or more of the Common Stock (or securities convertible into or exercisable for Common Stock) or the voting power of the Company on a post-transaction basis.

Exceptions:                                                                                  

(If no exceptions, write “none.” If left blank, response will be deemed to be “none.”)

6. The Investor confirms that it has had full access to all filings made by the Company with the SEC, including the Disclosure Package (as applicable), and that it was able to read, review, download and print each such filing prior to or in connection with the receipt of this Agreement along with the Company’s counterpart to this Agreement. On or promptly following the date hereof, the Company will file the Prospectus Supplement with the SEC containing certain supplemental information regarding the Company and the Offering.

[ Remainder of page intentionally left blank. Signature pages follow .]

Number of Shares:                                         

Aggregate Purchase Price: $                                         

Please confirm that the foregoing correctly sets forth the agreement between us by signing in the space provided below for that purpose.

[ Signature Page to Subscription Agreement ]

Agreed and accepted on January 29, 2009:

[ Signature Page to Subscription Agreement ]

ANNEX I

TERMS AND CONDITIONS FOR PURCHASE OF SHARES

1. Closings and Delivery of the Shares and Funds.

1.1. Closing . The completion of the purchase and sale of the Shares (the “ Closing ”) will occur at a place and time (the “ Closing Date ”) to be specified by the Company and the Placement Agent, and of which the Investor will be notified in advance by the Placement Agent. At the Closing, (a) the Company will cause the Transfer Agent to deliver to the Investor the number of Shares set forth on the signature page hereto registered in the name of the Investor or, if so indicated on the Investor Questionnaire attached hereto as Exhibit A , in the name of a nominee designated by the Investor and (b) the aggregate purchase price for the Shares being purchased by the Investor will be delivered by or on behalf of the Investor to the Company.

1.2. Placement Agent Fee . The Investor acknowledges that the Company intends to pay the Placement Agent a fee in respect of the sale of Shares to the Investor.

1.3. Delivery of Funds . No later than one (1) business day after the execution of this Agreement by the Investor and the Company , the Investor shall remit by wire transfer the amount of funds equal to the aggregate purchase price for the Shares being purchased