EX-5.1 2 dex51.htm OPINION OF COUNSEL AS TO LEGALITY OF SECURITIES BEING REGISTERED Opinion of counsel as to legality of securities being registered

EXHIBIT 5.1

June 30, 2006

Pharsight Corporation

321 E. Evelyn Ave, 3rd Fl

Mountain View, California 94041

Re: Registration Statement on Form S-8

Ladies and Gentlemen:

We have examined the Registration Statement on Form S-8 (the “Registration Statement”) to be filed by you with the Securities and Exchange Commission on or about June 30, 2006, in connection with the registration under the Securities Act of 1933, as amended, of an additional 785,630 shares of Common Stock (the “Shares”) to be issued under the Amended and Restated 2000 Equity Incentive Plan (the “Plan”).

It is our opinion that, when issued and sold pursuant to options granted in the manner described in the Plan, and pursuant to the agreements which accompany each option grant, the Shares will be legally and validly issued, fully paid and non-assessable.

We consent to the use of this opinion as an exhibit to the Registration Statement, and further consent to the use of our name wherever appearing in the Registration Statement and any amendments thereto.

 

Very truly yours,
WILSON SONSINI GOODRICH & ROSATI
Professional Corporation
/s/ Wilson Sonsini Goodrich & Rosati, P.C.