SECURITIES AND EXCHANGE COMMISSION
                          WASHINGTON, D.C. 20549

                                SCHEDULE TO
                               (RULE 13E-4)
         TENDER OFFER STATEMENT UNDER SECTION 14(D)(1) OR 13(E)(1)
                  OF THE SECURITIES EXCHANGE ACT OF 1934

                             HESKA CORPORATION
       (NAME OF SUBJECT COMPANY (ISSUER) AND FILING PERSON (OFFEROR)

   OPTIONS TO PURCHASE COMMON STOCK, PAR VALUE $0.001 PER SHARE, HAVING
              AN EXERCISE PRICE GREATER THAN $3.90 PER SHARE
                      (TITLE OF CLASS OF SECURITIES)

                                 42805E108
                   (CUSIP NUMBER OF CLASS OF SECURITIES)
                         (UNDERLYING COMMON STOCK)

                             ROBERT B. GRIEVE
             CHIEF EXECUTIVE OFFICER AND CHAIRMAN OF THE BOARD
                             HESKA CORPORATION
                           1613 PROSPECT PARKWAY
                       FORT COLLINS, COLORADO 80525
                              (970) 493-7272
(NAME, ADDRESS AND TELEPHONE NUMBER OF PERSON AUTHORIZED TO RECEIVE NOTICES
                                    AND
                COMMUNICATIONS ON BEHALF OF FILING PERSON)


                                 Copies to:
                           KAREN A. DEMPSEY, ESQ.
                          WILSON SONSINI GOODRICH &
                                   ROSATI
                          PROFESSIONAL CORPORATION
                           ONE MARKET, SPEAR TOWER
                                 SUITE 3300
                          SAN FRANCISCO, CALIFORNIA
                                    94105
                               (415) 947-2000

                            CALCULATION OF FILING FEE
        TRANSACTION VALUATION*                AMOUNT OF FILING FEE

                 $892,293.52                                $178.46

 * Calculated solely for purposes of determining the filing fee.  This
   amount assumes that options to purchase 1,068,615 shares of common stock
   of Heska Corporation having an aggregate value of $892,293.52 as of
   August 23, 2001 (based on the market value of the underlying common
   stock) will be exchanged pursuant to this offer. The amount of the filing
   fee, calculated in accordance with Rule 0-11(b) of the Securities
   Exchange Act of 1934, as amended, equals 1/50th of one percent of the
   value of the transaction.

   Check box if any part of the fee is offset as provided by
   Rule 0-11(a)(2) and identify the filing with which the offsetting fee
   was previously paid.  Identify the previous filing by registration
   statement number, or the Form or Schedule and the date of its filing.

                   Amount Previously Paid:  Not applicable.
                  Form or Registration No.:  Not applicable.
                        Filing party:  Not applicable.
                         Date filed:  Not applicable.

  Check box if the filing relates solely to preliminary communications
  made before the commencement of a tender offer.

  Check the appropriate boxes below to designate any transactions to
  which the statement relates:
       third party tender offer subject to Rule 14d-1.
       issuer tender offer subject to Rule 13e-4.
       going-private transaction subject to Rule 13e-3.
       amendment to Schedule 13D under Rule 13d-2.

  Check the following box if the filing is a final amendment reporting the
  results of the tender offer.


      ITEM 1.    SUMMARY TERM SHEET.

     The information set forth under the "Summary Term Sheet" section in the
Offer to Exchange, dated August 29, 2001, attached hereto as Exhibit (a)(1) (the
"Offer to Exchange"), is incorporated herein by reference.

ITEM 2.    SUBJECT COMPANY INFORMATION.

     (a)  The name of the issuer is Heska Corporation, a Delaware corporation
(the "Company"), and the address of its principal executive office is 1613
Prospect Parkway, Fort Collins, Colorado 80525, (970) 493-7272.  The information
set forth in the Offer to Exchange under Section 10 ("Information Concerning
Heska") is incorporated herein by reference.

     (b)  This Tender Offer Statement on Schedule TO relates to an offer by the
Company to exchange options having an exercise price greater than $3.90 per
share (the "Options") to purchase shares of the Company's common stock, par
value $0.001 per share, that are outstanding under the Company's 1997 Stock
Incentive Plan (the "1997 Plan") and held by current employees of the Company
for restricted shares of common stock (the "Restricted Stock"), upon the terms
and subject to the conditions described in the Offer to Exchange, and the
related Letter to Eligible Employees attached hereto as Exhibit (a)(2) (together
with the Offer of Exchange, as they may be amended or supplemented from time to
time, the "Offer").  As of August 29, 2001, the total number of shares of common
stock underlying the Options is 1,088,815 of which 1,068,615 underlying shares
are held by current employees who are eligible to participate in the Offer.
Only employees of Heska Corporation will be eligible to accept the Offer.
Employees of Diamond Animal Health, Inc., Heska AG and CMG-Heska Allergy
Products S.A., each a subsidiary of the Company, will not be eligible to
participate in the Offer.  In addition, outside directors will not be eligible
to accept the Offer.

     The number of shares of Restricted Stock to be issued will be equal to the
number of shares of common stock underlying the options that are accepted for
exchange and cancelled.  The information set forth in the Offer to Exchange
under "Summary Term Sheet", Section 2 ("Number of Options; Expiration Date") and
Section 9 ("Source and Amount of Consideration; Terms of Restricted Stock") is
incorporated herein by reference.

     (c)  The information set forth in the Offer to Exchange under Section 8
("Price Range of Shares Underlying the Options") is incorporated herein by
reference.

ITEM 3.    IDENTITY AND BACKGROUND OF FILING PERSON.

     (a)  The information set forth under Item 2(a) above is incorporated herein
by reference.

ITEM 4.    TERMS OF THE TRANSACTION.

     (a)  The information set forth in the Offer to Exchange under "Summary Term
Sheet," Section 1  ("Eligibility"), Section 2 ("Number of Options; Expiration
Date"), Section 4 ("Procedures for Tendering Options"), Section 5 ("Withdrawal
Rights and Change of Election"), Section 6 ("Acceptance of Options for Exchange
and Issuance of Restricted Stock"), Section 7 ("Conditions of the Offer"),
Section 9 ("Source and Amount of Consideration; Terms of Restricted Stock"),
Section 12 ("Status of Options Acquired by Us in the Offer; Accounting
Consequences of the Offer"), Section 13 ("Legal Matters; Regulatory Approvals"),
Section 14 ("Material U.S. Federal Income Tax Consequences") and Section 15
("Extension of Offer; Termination; Amendment") is incorporated herein by
reference.

     (b)  The information set forth in the Offer to Exchange under Section 11
("Interests of Directors and Officers; Transactions and Arrangements Concerning
the Options") is incorporated herein by reference.

ITEM 5.    PAST CONTACTS, TRANSACTIONS, NEGOTIATIONS AND ARRANGEMENTS.

     (e)  The information set forth in the Offer to Exchange under Section 11
("Interests of Directors and Officers; Transactions and Arrangements Concerning
the Options") is incorporated herein by reference.

ITEM 6.    PURPOSES OF THE TRANSACTION AND PLANS OR PROPOSALS.

     (a)  The information set forth in the Offer to Exchange under Section 3
("Purpose of the Offer") is incorporated herein by reference.

     (b)  The information set forth in the Offer to Exchange under Section 6
("Acceptance of Options for Exchange and Issuance of Restricted Stock") and
Section 12 ("Status of Options Acquired by Us in the Offer; Accounting
Consequences of the Offer") is incorporated herein by reference.

     (c)  The information set forth in the Offer to Exchange under Section 3
("Purpose of the Offer") is incorporated herein by reference.

ITEM 7.    SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

     (a)  The information set forth in the Offer to Exchange under Section 9
("Source and Amount of Consideration; Terms of Restricted Stock") and Section 16
("Fees and Expenses") is incorporated herein by reference.

     (b)  The information set forth in the Offer to Exchange under Section 7
("Conditions of the Offer") is incorporated herein by reference.

     (d)  Not applicable.

ITEM 8.    INTEREST IN SECURITIES OF THE SUBJECT COMPANY.

     (a)  The information set forth in the Offer to Exchange under Section 11
("Interests of Directors and Officers; Transactions and Arrangements Concerning
the Options") is incorporated herein by reference.

     (b)  The information set forth in the Offer to Exchange under Section 11
("Interests of Directors and Officers; Transactions and Arrangements Concerning
the Options") is incorporated herein by reference.

ITEM 9.    PERSON/ASSETS, RETAINED, EMPLOYED, COMPENSATED OR USED.

     (a)  Not applicable.

ITEM 10.   FINANCIAL STATEMENTS.

     (a)  The information set forth in the Offer to Exchange under Section 10
("Information Concerning Heska") and Section 17 ("Additional Information"), and
in Part I - Item 8 of the Company's Annual Report on Form 10-K for its fiscal
year ended December 31, 2000, as filed with the SEC on March 29, 2001, the
Company's Quarterly Report on Form 10-Q for its fiscal quarter ended March 31,
2001, as filed with the SEC on May 10, 2001, and the Company's Quarterly Report
on Form 10-Q for its fiscal quarter ended June 30, 2001, as filed with the SEC
on August 14, 2001, is incorporated herein by reference.

     (b)  Not applicable.

ITEM 11.   ADDITIONAL INFORMATION.

     (a)  The information set forth in the Offer to Exchange under Section 11
("Interests of Directors and Officers; Transactions and Arrangements About the
Options") and Section 13 ("Legal Matters; Regulatory Approvals") is incorporated
herein by reference.

     (b)  Not applicable.

ITEM 12.   EXHIBITS.

(a)(1) Offer to Exchange, dated August 29, 2001.

(a)(2) Form of Letter to Eligible Employees.

(a)(3) Form of Election Form.

(a)(4) Form of Notice to Withdraw from the Offer.

(a)(5) Form of Notice to Tendering Employees.

(a)(6) Heska Corporation Annual Report on Form 10-K for
       its fiscal year ended December 31, 2000, filed
       with the Securities and Exchange Commission on
       March 29, 2001 and incorporated herein by
       reference.

(a)(7) Heska Corporation Quarterly Report on Form 10-Q
       for its fiscal quarter ended March 31, 2001,
       filed with the Securities and Exchange Commission
       on May 10, 2001, and incorporated herein by
       reference.

(a)(8) Heska Corporation Quarterly Report on Form 10-Q
       for its fiscal quarter ended June 30, 2001, filed
       with the Securities and Exchange Commission on
       August 14, 2001, and incorporated herein by
       reference.

(d)(1)    Heska Corporation 1997 Stock Incentive Plan.

(d)(2)    Form of Restricted Stock Agreement.

  (g)      Not applicable.

  (h)      Not applicable.

ITEM 13.   INFORMATION REQUIRED BY SCHEDULE 13E-3.

 (a)       Not applicable.


                                    SIGNATURE


     After due inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this Schedule TO is true, complete and
correct.

                                   HESKA CORPORATION


                                  /s/  Robert B. Grieve
                                  ------------------------
                                   Robert B. Grieve
                                   Chief Executive Officer

Date: August 29, 2001


                                INDEX TO EXHIBITS



  EXHIBIT                        DESCRIPTION
   NUMBER

(a)(1) Offer to Exchange, dated August 29, 2001.

(a)(2) Form of Letter to Eligible Employees.

(a)(3) Form of Election Form.

(a)(4) Form of Notice to Withdraw from the Offer.

(a)(5) Form of Notice to Tendering Employees.

(a)(6) Heska Corporation Annual Report on Form 10-K for
       its fiscal year ended December 31, 2000, filed
       with the Securities and Exchange Commission on
       March 29, 2001 and incorporated herein by
       reference.

(a)(7) Heska Corporation Quarterly Report on Form 10-Q
       for its fiscal quarter ended March 31, 2001,
       filed with the Securities and Exchange Commission
       on May 10, 2001, and incorporated herein by
       reference.

(a)(8) Heska Corporation Quarterly Report on Form 10-Q
       for its fiscal quarter ended June 30, 2001, filed
       with the Securities and Exchange Commission on
       August 14, 2001, and incorporated herein by
       reference.

(d)(1)    Heska Corporation 1997 Stock Incentive Plan.

(d)(2)    Form of Restricted Stock Agreement.