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 *
BLAIR JAMES C
   2. Issuer Name and Ticker or Trading Symbol
TANDEM DIABETES CARE INC [TNDM] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
C/O DOMAIN ASSOCIATES, LLC, ONE PALMER SQUARE		 3. Date of Earliest Transaction (Month/Day/Year)
11/19/2013
(Street)

PRINCETON, NJ 08542		 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
Common Stock 11/19/2013   C   3,189,058 A (1) 3,189,058 I By Domain Partners VII, L.P.
Common Stock 11/19/2013   C   54,390 A (1) 54,390 I By DP VII Associates, L.P.

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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
Series B Preferred Stock (1) 11/19/2013   C     356,111   (1)   (1) Common Stock 356,111 $ 0 0 I By Domain Partners VII, L.P.
Series C Preferred Stock (1) 11/19/2013   C     549,833   (1)   (1) Common Stock 549,833 $ 0 0 I By Domain Partners VII, L.P.
Series D Preferred Stock (1) 11/19/2013   C     2,283,114   (1)   (1) Common Stock 2,283,114 $ 0 0 I By Domain Partners VII, L.P.
Warrant to Purchase Series D Preferred Stock $ 4.4 11/19/2013   J(2)     590,403   (3)   (3) Series D Preferred Stock 590,403 $ 0 0 I By Domain Partners VII, L.P.
Warrant to Purchase Common Stock $ 7.37 11/19/2013   J(2)   352,351     (4)   (4) Common Stock 352,351 $ 0 352,351 I By Domain Partners VII, L.P.
Series B Preferred Stock (1) 11/19/2013   C     6,071   (1)   (1) Common Stock 6,071 $ 0 0 I By DP VII Associates, L.P.
Series C Preferred Stock (1) 11/19/2013   C     9,378   (1)   (1) Common Stock 9,378 $ 0 0 I By DP VII Associates, L.P.
Series D Preferred Stock (1) 11/19/2013   C     38,941   (1)   (1) Common Stock 38,941 $ 0 0 I By DP VII Associates, L.P.
Warrant to Purchase Series D Preferred Stock $ 4.4 11/19/2013   J(2)     10,068   (5)   (5) Series D Preferred Stock 10,068 $ 0 0 I By DP VII Associates, L.P.
Warrant to Purchase Common Stock $ 7.37 11/19/2013   J(2)   6,008     (6)   (6) Common Stock 6,008 $ 0 6,008 I By DP VII Associates, L.P.

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
BLAIR JAMES C
C/O DOMAIN ASSOCIATES, LLC
ONE PALMER SQUARE
PRINCETON, NJ 08542		     X    

Signatures

 /s/Kathleen K. Schoemaker, Attorney-in-Fact   11/19/2013
**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) All outstanding shares of the Issuer's preferred stock automatically converted into Common Stock upon the closing of the Issuer's initial public offering (the "IPO"), for no additional consideration. The preferred stock had no expiration date. The Common Stock equivalents of the preferred stock reflect the 1 for 1.6756 reverse split of the Common Stock effected in November 2013.
(2) Upon the closing of the IPO the Warrants to purchase Series D Preferred Stock automatically converted into Warrants to purchase the number of shares of Common Stock that the Series D Preferred Stock underlying the Warrants were convertible into, subject to the reverse split described in footnote (1), and the exercise price accordingly adjusted to $7.37 per share.
(3) The Warrant to purchase Series D Preferred Stock was immediately exercisable and expired as follows: 362,965 shares on 8/17/21; 90,741 shares on 5/25/22; and 136,697 shares on 7/17/22.
(4) The Warrant to purchase Common Stock is immediately exercisable and expires as follows: 216,617 shares on 8/17/21; 54,154 shares on 5/25/22; and 81,580 shares on 7/17/22.
(5) The Warrant to purchase Series D Preferred Stock was immediately exercisable and expired as follows: 6,190 shares on 8/17/21; 1,547 shares on 5/25/22; and 2,331 shares on 7/17/22.
(6) The Warrant to purchase Common Stock is immediately exercisable and expires as follows: 3,694 shares on 8/17/21; 923 shares on 5/25/22; and 1,391 shares on 7/17/22.

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