FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
HOROWITZ COREY M
  2. Issuer Name and Ticker or Trading Symbol
NETWORK 1 SECURITY SOLUTIONS INC [NSSI-OTC]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director __X__ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
CEO & Chairman
(Last)
(First)
(Middle)
6 BROOKLAWN DRIVE
3. Date of Earliest Transaction (Month/Day/Year)
05/20/2011
(Street)

WESTPORT, CT 06880
4. If Amendment, Date Original Filed(Month/Day/Year)
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 Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Option to purchase common stock $ 0.68 05/20/2011   J   20,000   05/20/2011 10/20/2014 Common Stock 20,000 (1) 20,000 D  
Option to purchase common stock $ 0.13 05/20/2011   J   515,218   05/20/2011 12/12/2014 Common Stock 515,218 (1) 515,218 D  
Warrant to purchase common stock $ 0.68 05/20/2011   J   300,000   05/20/2011 07/11/2014 Common Stock 300,000 (1) 300,000 I (2) By CMH Capital Management Corp.

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
HOROWITZ COREY M
6 BROOKLAWN DRIVE
WESTPORT, CT 06880
  X   X   CEO & Chairman  

Signatures

 By: /s/ Corey M. Horowitz   05/24/2011
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(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) The expiration dates of the previously issued options and warrants were extended for three years by the Board of Directors on May 20, 2011.
(2) The warrants are owned directly by CMH Capital Management Corp. and indirectly by Corey M. Horowitz. CMH Capital Management Corp. is an entity in which Corey Horowitz is the sole officer, director and shareholder.

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

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