EXHIBIT 5.1
                        WILSON SONSINI GOODRICH & ROSATI
                                   One Market
             Spear Street Tower, Suite 1600 San Francisco, CA 94105
                               Tel: (415) 947-2000


                                  June 3, 2002


Heska Corporation
1613 Prospect Parkway
Fort Collins, CO 80525


Re:  Registration Statement on Form S-8


Ladies and Gentlemen:

     With reference to the Registration Statement on Form S-8 to be filed by
Heska Corporation, a Delaware corporation (the "Company"), with the Securities
and Exchange Commission under the Securities Act of 1933, as amended, relating
to 1,000,000 shares of the Company's Common Stock issuable pursuant to the
Company's Employee Stock Purchase (the "Stock Plan"), it is our opinion that
such shares of the Common Stock of the Company,  when  issued  and  sold in
accordance with the Stock Plan, will be legally issued, fully paid and
nonassessable.

     We hereby consent to the filing of this opinion with the Securities and
Exchange Commission as Exhibit 5.1 to the Registration Statement.

                                       Very truly yours,



                                       /s/  WILSON SONSINI GOODRICH & ROSATI