Ownership Submission
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, 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 *
  MPM BIOVENTURES II QP LP
2. Date of Event Requiring Statement (Month/Day/Year)
07/13/2005
3. Issuer Name and Ticker or Trading Symbol
CRYOCOR INC [CRYO]
(Last)
(First)
(Middle)
C/O MPM ASSET MANAGEMENT, 111 HUNTINGTON AVE., 31ST FLOOR
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

BOSTON, MA 02199
6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
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)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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 control number.

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 of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)
6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Series B Convertible Preferred Stock   (1)   (2) Common Stock 455,713 $ (3) I See Footnote (4)
Series C Convertible Preferred Stock   (1)   (2) Common Stock 795,280 $ (5) I See Footnote (6)
Series D Redeemable Convertible Preferred Stock   (1)   (2) Common Stock 1,471,388 $ (7) I See Footnote (8)
Warrant (right to buy)   (1)   (9) Common Stock 4,778 $ 13.02 I See Footnote (10)
Warrant (right to buy)   (1)   (11) Common Stock 121,940 $ 8.37 I See Footnote (12)

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
MPM BIOVENTURES II QP LP
C/O MPM ASSET MANAGEMENT
111 HUNTINGTON AVE., 31ST FLOOR
BOSTON, MA 02199
    X    
MPM BIOVENTURES II LP
C/O MPM ASSET MANAGEMENT
111 HUNTINGTON AVE., 31ST FLOOR
BOSTON, MA 02199
    X    
MPM BIOVENTURES II GMBH & CO PARALLEL BETEILIGUNGS KG
C/O MPM ASSET MANAGEMENT
111 HUNTINGTON AVE., 31ST FLOOR
BOSTON, MA 02199
    X    
MPM ASSET MANAGEMENT INVESTORS 2000B LLC
C/O MPM ASSET MANAGEMENT
111 HUNTINGTON AVE., 31ST FLOOR
BOSTON, MA 02199
    X    
MPM ASSET MANAGEMENT II LP
C/O MPM ASSET MANAGEMENT
111 HUNTINGTON AVE., 31ST FLOOR
BOSTON, MA 02199
    X    
MPM ASSET MANAGEMENT II LLC
C/O MPM ASSET MANAGEMENT
111 HUNTINGTON AVE., 31ST FLOOR
BOSTON, MA 02199
    X    
GADICKE ANSBERT
C/O MPM ASSET MANAGEMENT
111 HUNTINGTON AVE., 31ST FLOOR
BOSTON, MA 02199
    X    
STEINMETZ MICHAEL
C/O MPM ASSET MANAGEMENT
111 HUNTINGTON AVE., 31ST FLOOR
BOSTON, MA 02199
    X    
GALAKATOS NICHOLAS
C/O MPM ASSET MANAGEMENT
111 HUNTINGTON AVE., 31ST FLOOR
BOSTON, MA 02199
    X    
EVNIN LUKE
C/O MPM ASSET MANAGEMENT
111 HUNTINGTON AVE., 31ST FLOOR
BOSTON, MA 02199
    X    

Signatures

By Luke Evnin, manager of MPM Asset Management II LLC, the general partner of MPM Asset Management II, L.P., the general partner of MPM BioVentures II-QP, L.P /s/ Luke Evnin 07/13/2005
**Signature of Reporting Person Date

By Luke Evnin, manager of MPM Asset Management II LLC, the general partner of MPM Asset Management II, L.P.,the general partner of MPM BioVentures II, L.P /s/ Luke Evnin 07/13/2005
**Signature of Reporting Person Date

By Luke Evnin, member of MPM Asset Management II LLC, the general partner of MPM Asset Management II, L.P.,the general partner of MPM BioVentures GmbH and Co. Parallel-Beteiligungs KG /s/ Luke Evnin 07/13/2005
**Signature of Reporting Person Date

By Luke Evnin, manager of MPM Asset Management Investors 2000B LLC /s/ Luke Evnin 07/13/2005
**Signature of Reporting Person Date

By Luke Evnin, manager of MPM Asset Management II LLC, the general partner of MPM Asset Management II, L.P. /s/ Luke Evnin 07/13/2005
**Signature of Reporting Person Date

By Luke Evnin, manager of MPM Asset Managment II, LLC /s/ Luke Evnin 07/13/2005
**Signature of Reporting Person Date

/s/ Ansbert Gadicke 07/13/2005
**Signature of Reporting Person Date

/s/ Michael Steinmetz 07/13/2005
**Signature of Reporting Person Date

/s/ Nicholas Galakatos 07/13/2005
**Signature of Reporting Person Date

/s/ Luke Evnin 07/13/2005
**Signature of Reporting Person Date

Explanation of Responses:

* 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).
(1) Immediate.
(2) Not applicable.
(3) Each share of Series B Convertible Preferred Stock will convert automatically into shares of Common Stock on a 0.281249 for 1 basis immediately prior to the closing of the Issuer's initial public offering.
(4) The shares are held as follows: 306,787 by MPM BioVentures II-QP, L.P. ("BV II QP"), 33,859 by MPM BioVentures II, L.P. ("BV II"), 7,063 by MPM Asset Management Investors 2000B LLC ("AM 2000B") and 108,004 by MPM BioVentures GmbH & Co. Parallel-Beteiligungs KG ("BV KG"). MPM Asset Management II, L.P. ("AM II GP") and MPM Asset Management II LLC ("AM II LLC") are the direct and indirect general partners of BV II QP, BV II and BV KG. Luke Evnin, Ansbert Gadicke, Nicholas Galakatos, Michael Steinmetz and Kurt Wheeler are the members of AM II LLC and AM 2000B. Each member of the group disclaims beneficial ownership of the securities except to the extent of its pecuniary interest therein.
(5) Each share of Series C Convertible Stock will convert automatically into shares of Common Stock on a 0.237750 for 1 basis immediately prior to the closing of the Issuer's initial public offering.
(6) The shares are held as follows: 535,384 by BV II QP, 59,089 by BV II, 12,326 by AM 2000B and 188,481 by BV KG. Each member of the group disclaims beneficial ownership of the securities except to the extent of its pecuniary interest therein.
(7) Each share of Series D Redeemable Convertible Stock will convert automatically into shares of Common Stock on a 0.036272 for 1 basis immediately prior to the closing of the Issuer's initial public offering.
(8) The shares are held as follows: 990,540 by BV II QP, 109,323 by BV II, 22,805 by AM 2000B and 348,720 by BV KG. Each member of the group disclaims beneficial ownership of the securities except to the extent of its pecuniary interest therein.
(9) Expires November 8, 2006. All warrants terminate if and to the extent not exercised prior to the completion of the Issuer's initial public offering.
(10) The shares are held as follows: 3,217 by BV II QP, 355 by BV II, 74 by AM 2000B and 1,132 by BV KG. Each member of the group disclaims beneficial ownership of the securities except to the extent of its pecuniary interest therein.
(11) 60,970 of the shares expire on February 3, 2008 and 60,970 of the shares expire on March 28, 2008. All warrants terminate if and to the extent not exercised prior to the completion of the Issuer's initial public offering.
(12) The shares are held as follows: 82,092 by BV II QP, 9,060 by BV II, 1,888 by AM 2000B and 28,900 by BV KG. Each member of the group disclaims beneficial ownership of the securities except to the extent of its pecuniary interest therein.

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