EXHIBIT 5.1
 
                               OPINION OF COUNSEL
 
March 19, 1999
Cardima, Inc.
47266 Benicia Street
Fremont, CA 94538
 
Re: Cardima, Inc. (the "Company") Registration Statement on Form S-3
 
Ladies and Gentlemen:
 
   We have examined the Registration Statement on Form S-3 to be filed with the
Securities and Exchange Commission (the "Registration Statement"), in
connection with the registration under the Securities Act of 1933, as amended,
of 8,604,806 shares of the Company's Common Stock. As your counsel, we have
examined the proceedings taken in connection with the sale and issuance of the
above-referenced securities.
 
   It is our opinion that the above-referenced securities, when issued and sold
in the manner referred to in the Registration Statement, will be 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, including the Prospectus constituting a part thereof,
and any amendment thereto.
 
                                          Very truly yours,
 
                                          WILSON, SONSINI, GOODRICH & ROSATI
                                          Professional Corporation
 
                                          /s/  WILSON SONSINI GOODRICH &
                                           ROSATI