EXHIBIT 5.1

                      [PILLSBURY WINTHROP, LLP LETTERHEAD]

July 3, 2001


Cardima, Inc.
47266 Benicia Street
Fremont, California  94538


Ladies and Gentlemen:

     We are acting as counsel for Cardima, Inc., a Delaware corporation (the
"Company"), in connection with the registration under the Securities Act of
1933, as amended, of 18,795,092 shares of common stock, par value $.001 per
share (the "Common Stock"), of the Company.  In this regard we have participated
in the preparation of a Registration Statement on Form S-3 relating to such
shares of Common Stock.  Such Registration Statement, as amended, is herein
referred to as the "Registration Statement."

     In connection with the foregoing, we have examined the Amended and Restated
Certificate of Incorporation, the Bylaws of the Company, certificates of
officers of the Company and public officials, and such other documentation as we
have deemed necessary or advisable in order to render the opinions expressed
herein.

     Based upon the foregoing, we are of the opinion that the 18,795,092 shares
of Common Stock (the "Shares") have been duly authorized and legally issued and
the Shares are fully paid and nonassessable.

     We hereby consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement and to the use of our name under the caption "Legal
Matters" in the Registration Statement and in the Prospectus included therein.

                              Very truly yours,


                              /s/ PILLSBURY WINTHROP LLP