EXHIBIT 5.1

                                   May 27, 1998


CardioThoracic Systems, Inc.
10600 North Tantau Avenue
Cupertino, California  95014

RE:  REGISTRATION STATEMENT ON FORM S-8

Ladies and Gentlemen:

     We have examined the Registration Statement on Form S-8 to be filed by 
you with the Securities and Exchange Commission on May 27, 1998 (the 
"Registration Statement") in connection with the registration under the 
Securities Act of 1933, as amended, of an aggregate of 750,000 shares of your 
Common Stock, par value $0.001 per share (the "Shares"), (i) 150,000 shares 
of which are to be issued pursuant to the 1998 Nonstatutory Stock Option Plan 
and (ii) 600,000 shares of which are to be issued pursuant to the Incentive 
Stock Plan (collectively, the "Plans").  As legal counsel for CardioThoracic 
Systems, Inc., we have examined the proceedings taken and are familiar with 
the proceedings proposed to be taken by you in connection with the issuance 
and sale of the Shares pursuant to the Plans.

     It is our opinion that, when issued and sold in the manner described in 
the Plans and pursuant to the agreements which accompany each grant under the 
Plans, the Shares will be legally and validly issued, fully-paid and 
non-assessable.

     We consent to the use of this opinion as an exhibit to the Registration 
Statement, and further consent to the use of our name wherever appearing in 
the Registration Statement and any amendments thereto.

                              Very truly yours,

                              WILSON SONSINI GOODRICH & ROSATI
                              Professional Corporation

                              
                              /s/ WILSON SONSINI GOODRICH & ROSATI