December 22, 1997


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 December 22, 1997 (the 
"Registration Statement") in connection with the registration under the 
Securities Act of 1933, as amended, of 600,000 shares of your Common Stock, 
reserved for issuance pursuant to the Incentive Stock Plan, as amended (the 
"Plan").  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 of Common 
Stock of CardioThoracic Systems, Inc. (the "Shares") pursuant to the Plan.

    It is our opinion that the Shares, when issued and sold in the manner 
described in the Plan and pursuant to the agreement that accompanies each 
grant under the Plan, 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