o

Rule 13d-1(b)

x

Rule 13d-1(c)

o

Rule 13d-1(d)

(a)

Name of Issuer: Sourcefire, Inc. (the "Company")

(b)

Address of Issuer's Principal Executive Offices:

The Company's principal executive offices are located at 9770 Patuxent Woods Drive , Columbia, Maryland 21046.

(a)

Name of Person Filing:

This statement is filed by:

(i) Diker GP, LLC, a Delaware limited liability company ("Diker GP"), as the general partner to the Delaware limited partnership the Diker Value Tech Fund, LP (“VT”), Diker Value Tech QP Fund, LP (“VTQP”), Diker Micro-Value Fund, LP ("MV"), the Diker Micro-Value QP Fund, LP ("MVQP"), Diker Micro & Small Cap Fund LP (“MS”) and Diker M&S Cap Master Ltd (“MSCM”) with respect to the Stock directly owned by VT, VTQP, MV, MVQP, MS and MSCM (collectively, the "Diker Funds");

(ii) Diker Management, LLC, a Delaware limited liability company ("Diker Management"), as the investment manager of the Diker Funds, with respect to the shares of Common Stock held by the Diker Funds;

(iii) Charles M. Diker, a citizen of the United States, and the managing member of each of Diker GP and Diker Management, with respect to the shares of Common Stock subject to the control of Diker GP and Diker Management; and

(iv) Mark N. Diker, a citizen of the United States, and the managing member of each of Diker GP and Diker Management, with respect to the shares of Common Stock subject to the control of Diker GP and Diker Management.

The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." Any disclosures herein with respect to persons other than the Reporting Persons are made on information and belief after making inquiry to the appropriate party.

(b)

Address of Principal Business office or, if none, Residence:

The address of the business office of each of the Reporting Persons is 745 Fifth Avenue, Suite 1409, New York, New York 10151.

(c)

Citizenship:

Each of Diker GP and Diker Management is a Delaware limited liability company. Each of Charles M. Diker and Mark N. Diker is a United States citizen.

(d)

Title of Class of Securities: Common Stock (the "Common Stock").

(e)

CUSIP Number: 83616T108

(a)

Broker or dealer registered under Section 15 of the Act,

(b)

Bank as defined in Section 3(a)(6) of the Act,

(c)

Insurance Company as defined in Section 3(a)(19) of the Act,

(d)

Investment Company registered under Section 8 of the Investment Company Act of 1940,

(e)

Investment Adviser in accordance with Rule 13d-1 (b)(1)(ii)(E),

(f)

Employee Benefit Plan or Endowment Fund in accordance with 13d-1 (b)(1)(ii)(F),

(g)

Parent Holding Company or control person in accordance with Rule 13d-1 (b)(1)(ii)(G),

(h)

Savings Association as defined in Section 3(b) of the Federal Deposit Insurance Act,

(i)

Church Plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act of 1940,

(j)

Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

If this statement is filed pursuant to 13d-1(c), check this box: x

(a)

Amount Beneficially Owned:

A. Diker GP, LLC

(a) Amount beneficially owned: 1,449

(b) Percent of class: 0.01% The percentages used herein and in the rest of Item 4 are calculated based upon the 26,894,675 shares of Common Stock issued and outstanding as of the date of the Company's most recent filing on form 10-Q.

(c)(i) Sole power to vote or direct the vote: -0-

(ii) Shared power to vote or direct the vote: 1,449

(iii) Sole power to dispose or direct the disposition: -0-

(iv) Shared power to dispose or direct the disposition: 1,449

B. Diker Management, LLC

(a) Amount beneficially owned: 1,598

(b) Percent of class: 0.01%

(c)(i) Sole power to vote or direct the vote: -0-

(ii) Shared power to vote or direct the vote: 1,598

(iii) Sole power to dispose or direct the disposition: -0-

(iv) Shared power to dispose or direct the disposition: 1,598

Date: February 12, 2010

DIKER GP, LLC

By: /s/ MARK N. DIKER

Name: Mark N. Diker
Title: Managing Member

DIKER MANAGEMENT, LLC

By: /s/ MARK N. DIKER

Name: Mark N. Diker
Title: Managing Member

CHARLES M. DIKER, Individually

/s/ CHARLES M. DIKER

Name: Charles M. Diker

MARK N. DIKER, Individually

/s/ MARK N. DIKER

Name: Mark N. Diker