Ownership Submission
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, Section 17(a) of the Public Utility Holding Company Act of 1935 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 *
Siebert Lawrence A.
  2. Issuer Name and Ticker or Trading Symbol
CHEMBIO DIAGNOSTICS, INC. [CEMI]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director __X__ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
President
(Last)
(First)
(Middle)
3661 HORSEBLOCK RD
3. Date of Earliest Transaction (Month/Day/Year)
05/07/2009
(Street)

MEDFORD, NY 11763
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

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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
Options (right to buy) $ 0.48 05/07/2009   D     50,000 05/05/2004 05/04/2011 Common Stock 50,000 (1) 0 D  
Options (right to buy) $ 0.48 05/07/2009   D     10,000 04/17/2006 05/04/2011 Common Stock 10,000 (1) 0 D  
Options (right to buy) $ 0.48 05/07/2009   D     100,000   (2) 05/28/2011 Common Stock 100,000 (1) 0 D  
Options (right to buy) $ 0.13 05/07/2009   A   50,000   05/05/2004 05/04/2011 Common Stock 50,000 $ 0.13 50,000 D  
Options (right to buy) $ 0.13 05/07/2009   A   10,000   04/17/2006 05/04/2011 Common Stock 10,000 $ 0.13 10,000 D  
Options (right to buy) $ 0.13 05/07/2009   A   100,000     (2) 05/28/2011 Common Stock 100,000 $ 0.13 100,000 D  
Options (right to buy) $ 0.13 05/07/2009   A   400,000     (3) 05/07/2014 Common Stock 400,000 $ 0.13 400,000 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Siebert Lawrence A.
3661 HORSEBLOCK RD
MEDFORD, NY 11763
  X   X   President  

Signatures

 /s/ Lawrence A. Siebert   11/03/2009
**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 reporting person agreed to cancellation of an option granted to him in exchange for a new option having a lower price
(2) 50,000 options vested on each of 4/17/06 and 1/1/07
(3) 133,333 options vest on 05/7/10, 133,333 options vest on 05/7/11, and 133,334 options vest on 05/7/12

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