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                                                                     EXHIBIT 5.1



                                December 27, 2000

Cardiac Pathways Corporation
995 Benecia Avenue
Sunnyvale, California
94085

        RE: REGISTRATION STATEMENT ON FORM S-3

Ladies and Gentlemen:

        We have examined the Registration Statement on Form S-3 to be filed by
you with the Securities and Exchange Commission on or about December 27, 2000
(the "Registration Statement"), in connection with the registration under the
Securities Act of 1933, as amended, of a total of 5,858,823 shares of your
Common Stock (the "Shares"). We understand that the Shares are to be sold from
time to time on the Nasdaq National Market at prevailing prices or as otherwise
described in the Registration Statement. As legal counsel for Cardiac Pathways
Corporation, we have examined the proceedings taken by you in connection with
the sale of the Shares.

        It is our opinion that the Shares are legally and validly issued, fully
paid and nonassessable.

        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 to it.

                                      Very truly yours,

                                      /s/ WILSON SONSINI GOODRICH & ROSATI,
                                      Professional Corporation