UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): May 10, 2007

PHARSIGHT CORPORATION

(Exact name of registrant as specified in its charter)

Delaware	000-31253	77-0401273
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification Number)

321 E. Evelyn Ave. 3^rd Floor

Mountain View, CA 94041

(Address and zip code of principal executive offices)

(650) 314-3800

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 7.01. Regulation FD Disclosure

Pharsight Corporation will deliver investor and securities analyst presentations that include the slides filed as Exhibit 99.1 to this Current Report on Form 8-K, which are incorporated herein by reference.

This information is not “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, and is not incorporated by reference into any filing made pursuant to the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended. The furnishing of these slides is not intended to constitute a representation that such furnishing is required by Regulation FD or that the materials they contain include material information that is not otherwise publicly available.

Item 9.01. Financial Statements and Exhibits

(d) Exhibits

99.1 Slides to be shown during investor and securities analyst presentations.

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Signatures

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

PHARSIGHT CORPORATION
By:	/s/ William Frederick
	William Frederick
	Senior Vice President and Chief Financial Officer

Date: May 14 , 2007

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EXHIBIT INDEX

Exhibit Number
99.1	Slides to be shown during investor and securities analyst presentations.

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