EXHIBIT 5.1

                  OPINION OF BROBECK, PHLEGER & HARRISON LLP

                               December 23, 1998




CardioDynamics International Corporation
6175 Nancy Ridge Drive
Suite 300
San Diego, California 92121

    Re:  CardioDynamics International Corporation Registration Statement on 
         Form S-3 for Resale of 48,334 Shares of Common Stock

Ladies and Gentlemen:

          We have acted as counsel to CardioDynamics International Corporation,
a California corporation (the "Company"), in connection with the registration
for resale of 276,514 shares of Common Stock (the "Shares").  The Shares are
issuable upon exercise of certain Warrants, dated October 28, 1998,
respectively, as described in the Company's Registration Statement on Form S-3
("Registration Statement") filed with the Securities and Exchange Commission
under the Securities Act of 1933, as amended (the "Act").

          This opinion is being furnished in accordance with the requirements of
Item 16 of Form S-3 and Item 601(b)(5)(i) of Regulation S-B.

          We have reviewed the Company's charter documents, the corporate
proceedings taken by the Company in connection with the original issuance of the
Warrants, and a certificate of a Company officer regarding (among other things)
the Company's receipt of consideration upon the original issuance of the
Warrants.  Based on such review, we are of the opinion that the Shares, if, as
and when issued upon exercise of the Warrants in accordance with the terms of
the Warrants (including payment of the indicated exercise price), will be duly
authorized, validly issued, fully paid and nonassessable.

          We consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement and to the reference to this firm under the caption
"Legal Matters" in the prospectus which is part of the Registration Statement.
In giving this consent, we do not thereby admit that we are within the category
of persons whose consent is required under Section 7 of the Act, the rules and
regulations of the Securities and Exchange Commission promulgated thereunder, or
Item 509 of Regulation S-B.


                                  EXHIBIT 5.1

 
          This opinion letter is rendered as of the date first written above and
we disclaim any obligation to advise you of facts, circumstances, events or
developments which hereafter may be brought to our attention and which may
alter, affect or modify the opinion expressed herein.  Our opinion is expressly
limited to the matters set forth above and we render no opinion, whether by
implication or otherwise, as to any other matters relating to the Company or the
Shares.

                                 Very truly yours,

                                 /s/ Brobeck, Phleger & Harrison LLP
                                 BROBECK, PHLEGER & HARRISON LLP

                                  EXHIBIT 5.1