SEC FORM 3

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF 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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1. Name and Address of Reporting Person^*

Kitchen Jennifer

(Last)

(First)

(Middle)

C/O COSTAR GROUP, INC.

2 BETHESDA METRO CENTER, 10TH FLOOR

(Street)

BETHESDA

20814

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
12/12/2006

3. Issuer Name and Ticker or Trading Symbol
COSTAR GROUP INC [ CSGP ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	Sr. Vice President, Research

5. If Amendment, Date of 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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock, par value $0.01 per share	2,258⁽¹⁾	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Option to Acquire Common Stock	⁽²⁾	09/03/2013	Common Stock, par value $0.01 per share	1,000	$30.06	D
Option to Acquire Common Stock	⁽³⁾	09/08/2014	Common Stock	10,000	$44.86	D

Explanation of Responses:

1. Represents all shares of Common Stock owned, consisting of 201 shares of Common Stock and 2,057 shares of Common Stock subject to unvested Restricted Stock Grants.

2. One-half of the option is currently excercisable. The other half (500 shares) vests on September 4, 2007.

3. The option vests in four equal installments. The first two installments vested on September 9, 2005 and September 9, 2006. The last two installments vest on September 9, 2007 and September 9, 2008.

Remarks:

	/s/ Jonathan Coleman, Attorney-in-Fact	12/14/2006
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.