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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1. Name and Address of Reporting Person * Tumelty John B.   2. Issuer Name and Ticker or Trading Symbol Proto Labs Inc [PRLB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Managing Dir.-Proto Labs, Ltd. (Last) (First) (Middle) 5540 PIONEER CREEK DRIVE 3. Date of Earliest Transaction (Month/Day/Year) 09/21/2012 (Street) MAPLE PLAIN, MN 55359 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 09/21/2012   X(1)   20,601 A $ 1.79 20,601 D   Common Stock 09/21/2012   S(1)   20,601 D $ 33.6108 (2) 0 D   Common Stock 09/24/2012   X(1)   5,398 A $ 1.79 5,398 D   Common Stock 09/24/2012   S(1)   5,398 D $ 33.5 0 D   Common Stock 09/25/2012   X(1)   9,001 A $ 1.79 9,001 D   Common Stock 09/25/2012   S(3)   9,001 D $ 33.5227 (4) 0 D

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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

Warrant (right to buy)

$ 1.79

09/21/2012

X(1)

20,601

(5)

07/04/2016

Common Stock

20,601

$ 0

14,399

D

Warrant (right to buy)

$ 1.79

09/24/2012

X(1)

5,398

(5)

07/04/2016

Common Stock

5,398

$ 0

9,001

D

Warrant (right to buy)

$ 1.79

09/25/2012

X(1)

9,001

(5)

07/04/2016

Common Stock

9,001

$ 0

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Tumelty John B. 5540 PIONEER CREEK DRIVE MAPLE PLAIN, MN 55359			Managing Dir.-Proto Labs, Ltd.

Signatures

/s/ Julie M. Regnier, Attorney-in-Fact for John B. Tumelty		09/25/2012
**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)	Transaction effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on July 27, 2012.
(2)	Reflects the weighted average price of 20,601 shares of common stock of Proto Labs, Inc. sold by the reporting person in multiple transactions on September 21, 2012 with sale prices ranging from $33.50 to $33.85 per share. The reporting person undertakes to provide upon request by the U.S. Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
(3)	Transaction effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on July 27, 2012. The transactions reported on this Form 4 conclude the transactions contemplated by the Rule 10b5-1 trading plan.
(4)	Reflects the weighted average price of 9,001 shares of common stock of Proto Labs, Inc. sold by the reporting person in multiple transactions on September 25, 2012 with sale prices ranging from $33.50 to $33.64 per share. The reporting person undertakes to provide upon request by the U.S. Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
(5)	Fully vested.

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