Ownership Submission
FORM 3
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number: 3235-0104
Expires: January 31, 2005
Estimated average burden hours per response... 0.5

(Print or Type Responses)
1. Name and Address of Reporting Person *
  GULERI TIM
2. Date of Event Requiring Statement (Month/Day/Year)
03/08/2007
3. Issuer Name and Ticker or Trading Symbol
SOURCEFIRE INC [FIRE]
(Last)
(First)
(Middle)
2884 SAND HILL ROAD,, SUITE 100
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

MENLO PARK, CA 94025
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)
2. Amount of Securities Beneficially Owned
(Instr. 4)
3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)
4. Nature of Indirect Beneficial Ownership
(Instr. 5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)
2. Date Exercisable and Expiration Date
(Month/Day/Year)
3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)
4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)
6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Series A Convertible Preferred Stock   (1)   (1) Common Stock 1,573,072 (2) $ (1) I Held by limited partnerships (3) (4)
Series A Convertible Preferred Stock   (1)   (1) Common Stock 30,283 (2) $ (1) I Held by limited liability company (5)
Series B Convertible Preferred Stock   (6)   (6) Common Stock 785,682 (2) $ (6) I Held by limited partnerships (7) (8)
Series B Convertible Preferred Stock   (6)   (6) Common Stock 19,962 (2) $ (6) I Held by limited liability company (9)
Series C Convertible Preferred Stock   (6)   (6) Common Stock 551,457 (2) $ (6) I Held by limited partnerships (10) (11)
Series C Convertible Preferred Stock   (6)   (6) Common Stock 16,637 (2) $ (6) I Held by limited liability company (12)
Series D Convertible Preferred Stock   (6)   (6) Common Stock 274,492 (2) $ (6) I Held by limited partnerships (13) (14)
Series D Convertible Preferred Stock   (6)   (6) Common Stock 8,281 (2) $ (6) I Held by limited liability company (15)

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
GULERI TIM
2884 SAND HILL ROAD,
SUITE 100
MENLO PARK, CA 94025
  X      

Signatures

/s/ Tim A. Guleri 03/08/2007
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) These securities are immediately convertible or exercisable. These securities will be automatically converted into Common Stock on a 1 to 1.84723 basis upon the closing of the Issuer?s initial public offering.
(2) Gives effect of the conversion of the securities into Common Stock.
(3) Includes 843,363 shares held by Sierra Ventures VIII-A, L.P. ("Sierra VIII-A"), and 8,222 shares held by Sierra Ventures VIII-B, L.P. ("Sierra VIII-B").(Continued to footnote 4)
(4) (Continued from Footnote 3) Sierra Ventures Associates VIII, LLC ("SVA VIII") is the general partner of Sierra VIII-A and Sierra VIII-B and possesses voting and dispositive power over the shares held by Sierra VIII-A and Sierra VIII-B. The reporting person is a managing member of SVA VIII. SVA VIII also holds an additional 39,126 shares as nominee for its members. SVA VIII does not have voting or dispositive power over such shares. The reporting person disclaims beneficial ownership of the shares reported herein, except to the extent of his pecuniary interest therein.
(5) 5,465 shares are held in the name of Sierra Ventures Associates VII, LLC ("SVA VII") as nominee on behalf of Reporting Person and 10,929 shares are held in the name of SVA VIII, as nominee on behalf of Reporting Person.
(6) These securities are immediately convertible or exercisable. These securities will be automatically converted into Common Stock on a 1 to 0.61576 basis upon the closing of the Issuer?s initial public offering.
(7) Includes 1,263,638 shares held by Sierra Ventures VIII-A and 12,319 shares held by Sierra Ventures VIII-B.(Continued to Footnote 8)
(8) (Continued from Footnote 7) SVA VIII is the general partner of Sierra VIII-A and Sierra VIII-B and possesses voting and dispositive power over the shares held by Sierra VIII-A and Sierra VIII-B. The reporting person is a managing member of SVA VIII. SVA III also holds an additional 94,544 shares as nominee for its members. SVA VIII does not have voting or dispositive power over such shares. The reporting person disclaims beneficial ownership of the shares reported herein, except to the extent of his pecuniary interest therein.
(9) 10,805 shares are held in the name of SVA VII, as nominee on behalf of Reporting Person and 21,614 shares are held in the name of SVA VIII, as nominee on behalf of Reporting Person.
(10) Includes 886,928 shares held by Sierra VIII-A, and 8,646 shares held by Sierra VIII-B. (Continued onto Footnote 11).
(11) (Continued from Footnote 10) SVA VIII is the general partner of Sierra VIII-A and Sierra VIII-B and possesses voting and dispositive power over the shares held by Sierra VIII-A and Sierra VIII-B. The reporting person is a managing member of SVA VIII. SVA VIII also holds an additional 106,871 shares as nominee for its members. SVA VIII does not have voting or dispositive power over such shares. The reporting person disclaims beneficial ownership of the shares reported herein, except to the extent of his pecuniary interest therein.
(12) 7,694 shares are held in the name of SVA VII, as nominee on behalf of Reporting Person and 19,326 shares are held in the name of SVA VIII, as nominee on behalf of Reporting Person.
(13) Includes 441,455 shares held by Sierra Ventures VIII-A, and 4,324 shares held by Sierra Ventures VIII-B. (Continued to Footnote 14.)
(14) (Continued from Footnote 13)...SVA VIII is the general partner of Sierra VIII-A and Sierra VIII-B and possesses voting and dispositive power over the shares held by Sierra VIII-A and Sierra VIII-B. The reporting person is a managing mebmer of SVA VIII. SVA VIII also holds an additional 53,196 shares as nominee for its members. SVA VIII does not have voting or dispositive power over such shares. The reporting person disclaims beneficial ownership of the shares reported herein, except to the extent of his pecuniary interest therein.
(15) 3,830 shares are held in the name of SVA VII, as nominee on behalf of Reporting Person and 9,620 shares are held in the name of SVA VIII, as nominee on behalf of Reporting Person.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, See Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.