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 * HELLERSTEIN MARK A   2. Issuer Name and Ticker or Trading Symbol ST MARY LAND & EXPLORATION CO [SM] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) President, CEO & Chairman (Last) (First) (Middle) 1776 LINCOLN ST, STE 700 3. Date of Earliest Transaction (Month/Day/Year) 05/10/2006 (Street) DENVER, CO 80203 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; $.01 Par Value 05/10/2006   M   18,292 A $ 6.2188 109,761 D   Common Stock; $.01 Par Value 05/10/2006   M   15,568 A $ 8.75 125,329 D   Common Stock; $.01 Par Value 05/10/2006   M   32,490 A $ 4.625 157,819 D   Common Stock; $.01 Par Value 05/10/2006   M   53,748 A $ 6.1875 211,567 D   Common Stock; $.01 Par Value 05/10/2006   M   39,902 A $ 16.6563 251,469 D   Common Stock; $.01 Par Value 05/10/2006   S(1)   100,000 D $ 41.046 151,469 D   Common Stock; $.01 Par Value 05/10/2006   S(1)   60,000 D $ 41.076 91,469 D   Common Stock; $.01 Par Value 05/11/2006   M   9,680 A $ 16.6563 101,149 D   Common Stock; $.01 Par Value 05/11/2006   M   21,766 A $ 7.965 122,915 D   Common Stock; $.01 Par Value 05/11/2006   M   21,766 A $ 10.595 144,681 D   Common Stock; $.01 Par Value 05/11/2006   M   21,764 A $ 10.855 166,445 D   Common Stock; $.01 Par Value 05/11/2006   M   65,024 A $ 11.58 231,469 D   Common Stock; $.01 Par Value 05/11/2006   S(1)   40,000 D $ 41.6624 191,469 D   Common Stock; $.01 Par Value 05/11/2006   S(1)   100,000 D $ 41.1817 91,469 D

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
Stock Option (Right-to-Buy)	$ 6.2188	05/10/2006		M			18,292	(2)	12/31/2006	Common Stock	18,292	$ 0	0	D
Stock Option (Right-to-Buy)	$ 8.75	05/10/2006		M			15,568	(3)	12/31/2007	Common Stock	15,568	$ 0	0	D
Stock Option (Right-to-Buy)	$ 4.625	05/10/2006		M			32,490	(4)	12/31/2008	Common Stock	32,490	$ 0	0	D
Stock Option (Right-to-Buy)	$ 6.1875	05/10/2006		M			53,748	(5)	12/31/2009	Common Stock	53,748	$ 0	0	D
Stock Option (Right-to-Buy)	$ 16.6563	05/10/2006		M			39,902	(6)	12/31/2010	Common Stock	39,902	$ 0	9,680	D
Stock Option (Right-to-Buy)	$ 16.6563	05/11/2006		M			9,680	(6)	12/31/2010	Common Stock	9,680	$ 0	0	D
Stock Option (Right-to-Buy)	$ 7.965	05/11/2006		M			21,766	(7)	09/30/2011	Common Stock	21,766	$ 0	0	D
Stock Option (Right-to-Buy)	$ 10.595	05/11/2006		M			21,766	(8)	12/31/2011	Common Stock	21,766	$ 0	0	D
Stock Option (Right-to-Buy)	$ 10.855	05/11/2006		M			21,764	(9)	03/31/2012	Common Stock	21,764	$ 0	0	D
Stock Option (Right-to-Buy)	$ 11.58	05/11/2006		M			65,024	(10)	06/01/2012	Common Stock	65,024	$ 0	184,976	D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
HELLERSTEIN MARK A 1776 LINCOLN ST STE 700 DENVER, CO 80203			President, CEO & Chairman

Signatures

/s/ Karin M. Writer (Attorney-in-Fact)		05/12/2006
**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 sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by Mr. Hellerstein on May 8, 2006.
(2)	The option vested on December 31, 1996.
(3)	The option vested on December 31, 1997.
(4)	The option vested as follows: 8,332 shares on January 1, 2000, 14,976 shares on December 31, 2000 and 9,182 shares on December 31, 2001.
(5)	The option vested in four equal installments on December 31, 1999, 2000, 2001, and 2002.
(6)	The option vested in four equal installments on December 31, 2000, 2001, 2002, and 2003.
(7)	The option vested in four equal installments on September 30, 2001, 2002, 2003, and 2004.
(8)	The option vested in four equal installments on December 31, 2001, 2002, 2003, and 2004.
(9)	The option vested in four equal installments on March 31, 2002, 2003, 2004, and 2005.
(10)	The total option grant vests as follows: 50,000 shares on June 1, 2002, 50,000 shares on June 1, 2003, 75,000 shares on June 1, 2004, 75,000 shares on June 1, 2005, 125,000 shares on June 1, 2006, and 125,000 shares of June 1, 2007.

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