1
As filed with the Securities and Exchange Commission on February 14, 2001
                                                    Registration No. 333-_______
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                   ----------

                                    FORM S-3
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                                   ----------

                                HESKA CORPORATION
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

            DELAWARE                                         77-0192527
(STATE OR OTHER JURISDICTION OF                           (I.R.S. EMPLOYER
 INCORPORATION OR ORGANIZATION)                        IDENTIFICATION NUMBER)

                              1613 PROSPECT PARKWAY
                          FORT COLLINS, COLORADO 80525
                                 (970) 493-7272
    (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                  OF REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
                                   ----------
                                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, INCLUDING ZIP CODE, AND TELEPHONE NUMBER,
                   INCLUDING AREA CODE, OF AGENT FOR SERVICE)
                                   ----------
                                   Copies to:
                             KAREN A. DEMPSEY, ESQ.
                        WILSON SONSINI GOODRICH & ROSATI
                            PROFESSIONAL CORPORATION
                                   ONE MARKET
                         SPEAR STREET TOWER, SUITE 3300
                         SAN FRANCISCO, CALIFORNIA 94105
                                 (415) 947-2000
                               FAX: (415) 947-2099
                                   ----------

         APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: From
time to time after the effective date of this Registration Statement.

         If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box. [ ]

         If any of the securities being registered on this Form are to be
offered on a delayed or continuous basis pursuant to Rule 415 under the
Securities Act of 1933 (the "Securities Act"), other than securities offered
only in connection with dividend or interest reinvestment plans, check the
following box. [X]

         If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. [ ]

         If this Form is a post-effective amendment filed pursuant to Rule
462(c) under the Securities Act, check the following box and list the Securities
Act registration statement number of the earlier effective registration
statement for the same offering. [ ]

         If delivery of the prospectus is expected to be made pursuant to Rule
434, please check the following box. [ ]
                                   ----------

                         CALCULATION OF REGISTRATION FEE
 
 
====================================================================================================================================
                                                                       PROPOSED MAXIMUM       PROPOSED MAXIMUM
         TITLE OF EACH CLASS OF                 AMOUNT TO BE          OFFERING PRICE PER     AGGREGATE OFFERING        AMOUNT OF
      SECURITIES TO BE REGISTERED                REGISTERED                SHARE(1)               PRICE(1)         REGISTRATION FEE
----------------------------------------- ------------------------- ---------------------- ---------------------- ------------------
                                                                                                    
Common Stock, $0.001 par value per           4,573,000 shares             $1.1875              $5,430,438              $1,358
 share
====================================================================================================================================

(1) The price of $1.1875 per share, which was the average of the high and low
    prices of the Registrant's Common Stock on the Nasdaq National Market on
    February 9, 2001, is set forth solely for the purposes of calculating the
    registration fee in accordance with Rule 457(c) of the Securities Act.
                                   ----------

         THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE
OR DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT
SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME EFFECTIVE ON
SUCH DATE AS THE SECURITIES AND EXCHANGE COMMISSION, ACTING PURSUANT TO SECTION
8(a), MAY DETERMINE.
================================================================================
   2

THE INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. THESE
SECURITIES MAY NOT BE SOLD UNTIL THE REGISTRATION STATEMENT FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION IS EFFECTIVE. THIS PROSPECTUS IS NOT AN OFFER
TO SELL THESE SECURITIES AND IT IS NOT SOLICITING AN OFFER TO BUY THESE
SECURITIES IN ANY STATE WHERE THE OFFER OR SALE IS NOT PERMITTED.


PROSPECTUS

(Subject to Completion, dated February 14, 2001)

                                4,573,000 Shares

                                  [HESKA LOGO]

                                HESKA CORPORATION

                                  Common Stock

                                   ----------

         This prospectus relates to the public offering, which is not being
underwritten, of up to 4,573,000 shares of our Common Stock which is held by
some of our current stockholders. We issued these shares of our Common Stock to
the selling stockholders identified in this prospectus in a private placement.

         The prices at which such stockholders may sell the shares will be
determined by the prevailing market price for the shares or in negotiated
transactions. We will not receive any of the proceeds from the sale of the
shares.

         Our Common Stock is listed on the Nasdaq National Market under the
symbol "HSKA." On February 13, 2001, the closing price for our Common Stock was
$1.125 per share.

                                   ----------

         INVESTING IN OUR COMMON STOCK INVOLVES CERTAIN RISKS. SEE "RISK
FACTORS" BEGINNING ON PAGE 3.

                                   ----------

         THE SECURITIES AND EXCHANGE COMMISSION AND STATE SECURITIES REGULATORS
HAVE NOT APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS
PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

                                   ----------

                The date of this Prospectus is ___________, 2001.



   3



         No person has been authorized to give any information or to make any
representations other than those contained in this prospectus in connection with
the offering made hereby, and if given or made, such information or
representations must not be relied upon as having been authorized by Heska
Corporation (referred to in this prospectus as "Heska," the "Company" and "we"),
any selling stockholder or by any other person. Neither the delivery of this
prospectus nor any sale made hereunder shall, under any circumstances, create
any implication that information herein is correct as of any time subsequent to
the date hereof. This prospectus does not constitute an offer to sell or a
solicitation of an offer to buy any security other than the securities covered
by this prospectus, nor does it constitute an offer to or solicitation of any
person in any jurisdiction in which such offer or solicitation may not lawfully
be made.

                       WHERE YOU CAN FIND MORE INFORMATION

         We file annual, quarterly and special reports, proxy statements and
other information with the Securities and Exchange Commission. You may read and
copy any document we file at the SEC's Public Reference Rooms in Washington,
D.C., New York, New York and Chicago, Illinois. The Public Reference Room in
Washington, D.C. is located at 450 Fifth Street, N.W. Please call the SEC at
1-800-SEC-0330 for further information on the public conference rooms. Our SEC
filings are also available to the public from the SEC's web site at
http://www.sec.gov.

         The SEC allows us to "incorporate by reference" the information we file
with them, which means that we can disclose important information to you by
referring you to those documents. The information incorporated by reference is
considered to be part of this prospectus, and later information filed with the
SEC will update and supersede this information. We incorporate by reference the
documents listed below and any future filings made with the SEC under Section
13a, 13(c), 14 or 15(d) of the Securities Exchange Act of 1934 (the "Exchange
Act") until our offering is completed.

         (1)      Heska's Annual Report on Form 10-K, for the year ended
                  December 31, 1999;

         (2)      Heska's Quarterly Report on Form 10-Q for the quarter ended
                  March 31, 2000;

         (3)      Heska's Quarterly Report on Form 10-Q for the quarter ended
                  June 30, 2000;

         (4)      Heska's Quarterly Report on Form 10-Q for the quarter ended
                  September 30, 2000;

         (5)      Heska's Current Report on Form 8-K filed with the Securities
                  and Exchange Commission on February 7, 2001; and

         (6)      The description of our Common Stock contained in our
                  Registration Statement on Form 8-A, filed with the Securities
                  and Exchange Commission on April 24, 1997, and any further
                  amendment or report filed hereafter for the purpose of
                  updating any such description.

         You may request a copy of these filings, at no cost, by writing or
telephoning us at the following address:

         Heska Corporation
         1613 Prospect Parkway
         Fort Collins, Colorado 80525
         (970) 493-7272


                                      -2-
   4



         You should rely only on the information incorporated by reference or
provided in this prospectus or the prospectus supplement. We have authorized no
one to provide you with different information. We are not making an offer of
these securities in any state where the offer is not permitted. You should not
assume that the information in this prospectus or the prospectus supplement is
accurate as of any date other than the date on the front of the document.

                                HESKA CORPORATION

         We discover, develop, manufacture and market companion animal health
products. We have a sophisticated scientific effort devoted to applying
biotechnology to create a broad range of diagnostic, therapeutic and vaccine
products for the large and growing companion animal health market. In addition
to our diagnostic, therapeutic and vaccine products, we also sell veterinary
diagnostic and patient monitoring instruments and offer diagnostic services in
the United States and Europe to veterinarians. Our principal executive offices
are located at 1613 Prospect Parkway, Fort Collins, Colorado 80525 and our
telephone number is (970) 493-7272.

                           FORWARD-LOOKING STATEMENTS

         This prospectus and the documents incorporated herein by reference
contain forward-looking statements within the meaning of Section 27A of the
Securities Act of 1933, as amended (the "Securities Act") and Section 21E of the
Exchange Act. Words such as "anticipates," "expects," "intends," "plans,"
"believes," "seeks," "estimates," variations of such words and similar
expressions are intended to identify such forward-looking statements. These
statements are not guarantees of future performance and are subject to certain
risks, uncertainties and assumptions that are difficult to predict. Therefore,
actual results could differ materially from those expressed or forecasted in any
such forward-looking statements as a result of certain factors, including those
set forth in "Risk Factors," as well as those noted in the documents
incorporated herein by reference. In connection with forward-looking statements
that appear in these disclosures, investors should carefully review the factors
set forth in this prospectus under "Risk Factors."

                                  RISK FACTORS

         Our future operating results may vary substantially from period to
period due to a number of factors, many of which are beyond our control. The
following discussion highlights some of these factors and the possible impact of
these factors on future results of operations. You should carefully consider
these factors before making an investment decision. If any of the following
factors actually occur, our business, financial condition or results of
operations could be harmed. In that case, the price of our common stock could
decline, and you could experience losses on your investment.

WE HAVE A HISTORY OF LOSSES AND MAY NEVER ACHIEVE PROFITABILITY.

         We have incurred net losses since our inception in 1988 and, as of
September 30, 2000, we had an accumulated deficit of $169.0 million. We
anticipate that we will continue to incur additional operating losses in the
near term. These losses have resulted principally from expenses incurred in our
research and development programs and from general and administrative and sales
and marketing expenses. Even if we achieve profitability, we may not be able to
sustain or increase profitability on a quarterly or annual basis.


                                      -3-
   5
WE MAY NEED ADDITIONAL CAPITAL IN THE FUTURE.

         We have incurred negative cash flow from operations since inception in
1988. We do not expect to generate positive cash flow sufficient to fund our
operations in the near term. Moreover, based on our current projections,
including the proceeds of our recent private placement, we may need to raise
additional capital in the future. If necessary, we expect to raise this
additional capital through one or more of the following:

         o        sale of additional securities;

         o        sale of various assets;

         o        licensing of technology; and

         o        sale of various products or marketing rights.

         Additional capital may not be available on acceptable terms, if at all.
Furthermore, any additional equity financing would likely be dilutive to
stockholders, and additional debt financing, if available, may include
restrictive covenants which may limit our currently planned operations and
strategies. If adequate funds are not available, we may be required to curtail
our operations significantly and reduce discretionary spending to extend
currently available cash resources, or to obtain funds by entering into
collaborative agreements or other arrangements on unfavorable terms. If we fail
to generate adequate funding on acceptable terms when we need to, our business
could be substantially harmed. Our auditors have informed us that if we are
unable to generate adequate funding for operations through December 31, 2001 by
the time our Form 10-K for the year ended December 31, 2000 is filed, their
report on our financial statements for the year ended December 31, 2000 will
include an explanatory fourth paragraph because of substantial doubt regarding
our ability to continue as a going concern.

WE HAVE LIMITED RESOURCES TO DEVOTE TO PRODUCT DEVELOPMENT AND
COMMERCIALIZATION. IF WE ARE NOT ABLE TO DEVOTE RESOURCES TO PRODUCT DEVELOPMENT
AND COMMERCIALIZATION, WE MAY NOT BE ABLE TO DEVELOP OUR PRODUCTS.

         Our strategy is to develop a broad range of products addressing
companion animal healthcare. We believe that our revenue growth and
profitability, if any, will substantially depend upon our ability to:

         o        improve market acceptance of our current products;

         o        complete development of new products; and

         o        successfully introduce and commercialize new products.

         We have introduced some of our products only recently and many of our
products are still under development. Because we have limited resources to
devote to product development and commercialization, any delay in the
development of one product or reallocation of resources to product development
efforts that prove unsuccessful may delay or jeopardize the development of our
other product candidates. If we fail to develop new products and bring them to
market, our ability to generate revenues will decrease.

OUR SUCCESS DEPENDS ON COMMERCIALIZING OUR PRODUCTS.

         Because several of our current products, as well as a number of
products under development, are unproven, we may need to expend substantial
efforts in order to educate our customers about the uses of our products and to
convince them of the need for our products. Our products may not achieve
satisfactory market acceptance, and we may not successfully commercialize them
on a timely basis, or at all. If any of our products do not achieve a
significant level of market acceptance, demand for our products will not develop
as expected and it is unlikely that we ever will become profitable.



                                      -4-
   6


WE MUST OBTAIN AND MAINTAIN COSTLY REGULATORY APPROVALS IN ORDER TO MARKET OUR
PRODUCTS.

         Many of the products we develop and market are subject to extensive
regulation by one or more of the United States Department of Agriculture, or
USDA, the Food and Drug Administration, or FDA, the Environmental Protection
Agency, or EPA, and foreign regulatory authorities. These regulations govern,
among other things, the development, testing, manufacturing, labeling, storage,
premarket approval, advertising, promotion, sale and distribution of our
products. Satisfaction of these requirements can take several years and time
needed to satisfy them may vary substantially, based on the type, complexity and
novelty of the product. The effect of government regulation may be to delay or
to prevent marketing of our products for a considerable period of time and to
impose costly procedures upon our activities. We have experienced in the past,
and may experience in the future, difficulties that could delay or prevent us
from obtaining the regulatory approval or license necessary to introduce or
market our products. Regulatory approval of our products may also impose
limitations on the indicated or intended uses for which our products may be
marketed.

         Among the conditions for regulatory approval is the requirement that
our manufacturing facilities or those of our third party manufacturers conform
to current Good Manufacturing Practices. The FDA and foreign regulatory
authorities strictly enforce Good Manufacturing Practices requirements through
periodic inspections. We can provide no assurance that any regulatory authority
will determine that our manufacturing facilities or those of our third party
manufacturers will conform to Good Manufacturing Practices requirements. Failure
to comply with applicable regulatory requirements can result in sanctions being
imposed on us or the manufacturers of our products, including warning letters,
product recalls or seizures, injunctions, refusal to permit products to be
imported into or exported out of the United States, refusals of regulatory
authorities to grant approval or to allow us to enter into government supply
contracts, withdrawals of previously approved marketing applications, civil
fines and criminal prosecutions.

FACTORS BEYOND OUR CONTROL MAY CAUSE OUR OPERATING RESULTS TO FLUCTUATE, AND
SINCE MANY OF OUR EXPENSES ARE FIXED, THIS FLUCTUATION COULD CAUSE OUR STOCK
PRICE TO DECLINE.

         We believe that our future operating results will fluctuate on a
quarterly basis due to a variety of factors, including:

         o        the introduction of new products by us or by our competitors;

         o        market acceptance of our current or new products;

         o        regulatory and other delays in product development;

         o        product recalls;

         o        competition and pricing pressures from competitive products;

         o        manufacturing delays;

         o        shipment problems;

         o        product seasonality; and

         o        changes in the mix of products sold.

         We have high operating expenses for personnel, new product development
and marketing. Many of these expenses are fixed in the short term. If any of the
factors listed above cause our revenues to decline, our operating results could
be substantially harmed.

         Our operating results in some quarters may not meet the expectations of
stock market analysts and investors. In that case, our stock price probably
would decline.


                                      -5-
   7


WE MUST MAINTAIN VARIOUS FINANCIAL AND OTHER COVENANTS UNDER OUR REVOLVING LINE
OF CREDIT AGREEMENT.

         Under our revolving line of credit agreement with Wells Fargo Business
Credit, Inc., we are required to comply with various financial and non-financial
covenants, and we have made various representations and warranties. Among the
financial covenants are requirements for monthly minimum book net worth, minimum
quarterly net income and minimum cash balances or liquidity levels. Failure to
comply with any of the covenants, representations or warranties would negatively
impact our ability to borrow under the agreement. Our inability to borrow to
fund our operations could materially harm our business.

A SMALL NUMBER OF LARGE CUSTOMERS ACCOUNT FOR A LARGE PERCENTAGE OF OUR
REVENUES, AND THE LOSS OF ANY OF THEM COULD HARM OUR OPERATING RESULTS.

         We currently derive a substantial portion of our revenues from sales by
our subsidiary Diamond, which manufactures various of our products and products
for other companies in the animal health industry. Revenues from two Diamond
customers comprised approximately 26% of our total revenues in the first nine
months of 2000. No customer accounted for more than 10% of our total revenue
during the nine months ended September 30, 1999. If we are not successful in
maintaining our relationships with our customers and obtaining new customers,
our business and results of operations will suffer.

WE OPERATE IN A HIGHLY COMPETITIVE INDUSTRY, WHICH COULD RENDER OUR PRODUCTS
OBSOLETE OR SUBSTANTIALLY LIMIT THE VOLUME OF PRODUCTS THAT WE SELL. THIS WOULD
LIMIT OUR ABILITY TO COMPETE AND ACHIEVE PROFITABILITY.

         We compete with independent animal health companies and major
pharmaceutical companies that have animal health divisions. Companies with a
significant presence in the animal health market, such as American Home
Products, Bayer, IDEXX Laboratories, Inc., Intervet International B.V., Merial
Ltd., Novartis, Pfizer Inc., Pharmacia & Upjohn, Inc. and Schering Plough
Corporation, have developed or are developing products that compete with our
products or would compete with them if developed. These competitors may have
substantially greater financial, technical, research and other resources and
larger, better-established marketing, sales, distribution and service
organizations than us. In addition, IDEXX, which has products that compete with
our heartworm diagnostic products, prohibits its distributors from selling
competitors' products, including ours. Our competitors offer broader product
lines and have greater name recognition than we do. Our competitors may develop
or market technologies or products that are more effective or commercially
attractive than our current or future products, or that would render our
technologies and products obsolete. Further, additional competition could come
from new entrants to the animal healthcare market. Moreover, we may not have the
financial resources, technical expertise or marketing, distribution or support
capabilities to compete successfully. If we fail to compete successfully, our
ability to achieve profitability will be limited.

WE HAVE LIMITED EXPERIENCE IN MARKETING OUR PRODUCTS, AND MAY BE UNABLE TO
COMMERCIALIZE OUR PRODUCTS.

         The market for companion animal healthcare products is highly
fragmented, with discount stores and specialty pet stores accounting for a
substantial percentage of sales. Because we sell our companion animal health
products only to veterinarians, we may fail to reach a substantial segment of
the potential market, and we may not be able to offer our products at prices
which are competitive with those of companies that distribute their products
through retail channels. We currently market our products to veterinarians
through a direct sales force and through third parties. To be successful, we
will have to continue to develop and train our direct sales force or rely on
marketing partnerships or other arrangements with third parties to market,
distribute and sell our products. We may not successfully develop and maintain
marketing, distribution or


                                      -6-
   8


sales capabilities, and we may not be able to make arrangements with third
parties to perform these activities on satisfactory terms. If we fail to develop
a successful marketing strategy, our ability to commercialize our products and
generate revenues will decrease.

WE HAVE GRANTED THIRD PARTIES SUBSTANTIAL MARKETING RIGHTS TO OUR PRODUCTS UNDER
DEVELOPMENT. IF OUR CURRENT THIRD PARTY MARKETING AGREEMENTS ARE NOT SUCCESSFUL,
OR IF WE ARE UNABLE TO DEVELOP OUR OWN MARKETING CAPABILITIES OR ENTER INTO
ADDITIONAL MARKETING AGREEMENTS IN THE FUTURE, WE MAY NOT BE ABLE TO DEVELOP AND
COMMERCIALIZE OUR PRODUCTS.

         We have granted marketing rights to various of our products under
development to third parties, including Novartis, Eisai and Ralston Purina.
Novartis has the right to manufacture and market throughout the world (except in
countries where Eisai has such rights) under the Novartis trade name any flea
control vaccine or feline heartworm vaccine we develop on or before December 31,
2005. We have retained the right to co-exclusively manufacture and market these
products throughout the world under our own trade names. Accordingly, we and
Novartis may become direct competitors, with each party sharing revenues on the
other's sales. We have also granted Novartis a right of first refusal pursuant
to which, prior to granting rights to any third party for any products or
technology we develop or acquire for either companion animal or food animal
applications, we must first offer Novartis such rights. In Japan, Novartis also
has the exclusive right, upon regulatory approval, to distribute our (1)
heartworm diagnostic products, (2) trivalent and bivalent feline vaccines and
(3) various other Heska products. Eisai has exclusive rights in Japan and most
countries in East Asia to market our feline and canine heartworm vaccines, and
our feline and canine flea control vaccines. In addition, we have granted
Ralston Purina the exclusive rights to develop and commercialize our
discoveries, know-how and technologies in various companion animal nutritional
products.

         Our agreements with our corporate marketing partners generally contain
no minimum purchase requirements in order for them to maintain their exclusive
or co-exclusive marketing rights. Novartis, Eisai or Ralston Purina or any other
collaborative party may not devote sufficient resources to marketing our
products. Furthermore, there is nothing to prevent Novartis, Eisai or Ralston
Purina or any other collaborative party from pursuing alternative technologies
or products that may compete with our products. If we fail to develop and
maintain our own marketing capabilities, we may find it necessary to continue to
rely on potential or actual competitors for third-party marketing assistance.
Third party marketing assistance may not be available in the future on
reasonable terms, if at all. If any of these events occur, we may not be able to
develop and commercialize our products and our revenues will decline.

WE MAY FACE COSTLY INTELLECTUAL PROPERTY DISPUTES.

         Our ability to compete effectively will depend in part on our ability
to develop and maintain proprietary aspects of our technology and either to
operate without infringing the proprietary rights of others or to obtain rights
to technology owned by third parties. We have United States and foreign-issued
patents and are currently prosecuting patent applications in the United States
and with various foreign countries. Our pending patent applications may not
result in the issuance of any patents or that any issued patents will offer
protection against competitors with similar technology. Patents we receive may
be challenged, invalidated or circumvented in the future or the rights created
by those patents may not provide a competitive advantage. We also rely on trade
secrets, technical know-how and continuing invention to develop and maintain our
competitive position. Others may independently develop substantially equivalent
proprietary information and techniques or otherwise gain access to our trade
secrets.

         The biotechnology and pharmaceutical industries have been characterized
by extensive litigation relating to patents and other intellectual property
rights. In 1998, Synbiotics Corporation filed a lawsuit


                                      -7-
   9


against us alleging infringement of a Synbiotics patent relating to heartworm
diagnostic technology, and this litigation remains ongoing. We may become
subject to additional patent infringement claims and litigation in the United
States or other countries or interference proceedings conducted in the United
States Patent and Trademark Office to determine the priority of inventions. The
defense and prosecution of intellectual property suits, USPTO interference
proceedings, and related legal and administrative proceedings are costly,
time-consuming and distracting. We may also need to pursue litigation to enforce
any patents issued to us or our collaborative partners, to protect trade secrets
or know-how owned by us or our collaborative partners, or to determine the
enforceability, scope and validity of the proprietary rights of others. Any
litigation or interference proceeding will result in substantial expense to us
and significant diversion of the efforts of our technical and management
personnel. Any adverse determination in litigation or interference proceedings
could subject us to significant liabilities to third parties. Further, as a
result of litigation or other proceedings, we may be required to seek licenses
from third parties which may not be available on commercially reasonable terms,
if at all.

         We license technology from a number of third parties. The majority of
these license agreements impose due diligence or milestone obligations on us,
and in some cases impose minimum royalty and/or sales obligations on us, in
order for us to maintain our rights under these agreements. Our products may
incorporate technologies that are the subject of patents issued to, and patent
applications filed by, others. As is typical in our industry, from time to time
we and our collaborators have received, and may in the future receive, notices
from third parties claiming infringement and invitations to take licenses under
third party patents. It is our policy that when we receive such notices, we
conduct investigations of the claims they assert. With respect to the notices we
have received to date, we believe, after due investigation, that we have
meritorious defenses to the infringement claims asserted. Any legal action
against us or our collaborators may require us or our collaborators to obtain
one or more licenses in order to market or manufacture affected products or
services. However, we cannot assure you that we or our collaborators will be
able to obtain licenses for technology patented by others on commercially
reasonable terms, that we will be able to develop alternative approaches if
unable to obtain licenses, or that the current and future licenses will be
adequate for the operation of our businesses. Failure to obtain necessary
licenses or to identify and implement alternative approaches could prevent us
and our collaborators from commercializing our products under development and
could substantially harm our business.

WE HAVE LIMITED MANUFACTURING EXPERIENCE AND CAPACITY AND RELY SUBSTANTIALLY ON
THIRD PARTY MANUFACTURERS. THE LOSS OF ANY THIRD PARTY MANUFACTURERS COULD LIMIT
OUR ABILITY TO LAUNCH OUR PRODUCTS IN A TIMELY MANNER, OR AT ALL.

         To be successful, we must manufacture, or contract for the manufacture
of, our current and future products in compliance with regulatory requirements,
in sufficient quantities and on a timely basis, while maintaining product
quality and acceptable manufacturing costs. In order to increase our
manufacturing capacity, we acquired Diamond in April 1996 and Center
Laboratories, Inc., or Center, in July 1997. Center was sold in June 2000. We
must complete significant improvements in our manufacturing infrastructure in
order to scale up for the manufacturing of our new products. We may not complete
such work successfully or on a timely basis.

         We currently rely on third parties to manufacture those products we do
not manufacture at our Diamond facility. We currently have supply agreements
with Quidel Corporation for various manufacturing services relating to our
point-of-care diagnostic tests and with Centaq, Inc. for the manufacture of our
own allergy immunotherapy treatment sets. Our manufacturing strategy presents
the following risks:


                                      -8-
   10


         o Delays in the scale-up to quantities needed for product development
           could delay regulatory submissions and commercialization of our
           products in development;

         o Our manufacturing facilities and those of our third party
           manufacturers are subject to ongoing periodic unannounced inspection
           by regulatory authorities, including the FDA, USDA and other federal
           and state agency's for compliance with strictly enforced Good
           Manufacturing Practices regulations and similar foreign standards,
           and we do not have control over our third-party manufacturers'
           compliance with these regulations and standards;

         o If we need to change to other commercial manufacturing contractors,
           additional regulatory licenses or approvals must be obtained for
           these contractors prior to our use. This would require new testing
           and compliance inspections. Any new manufacturer would have to be
           educated in, or develop substantially equivalent processes necessary
           for the production of our products;

         o If market demand for our products increases suddenly, our current
           manufacturers might not be able to fulfill our commercial needs,
           which would require us to seek new manufacturing arrangements and may
           result in substantial delays in meeting market demand; and

         o We may not have intellectual property rights, or may have to share
           intellectual property rights, to any improvements in the
           manufacturing processes or new manufacturing processes for our
           products.

         Any of these factors could delay commercialization of our products
under development, interfere with current sales, entail higher costs and result
in our being unable to effectively sell our products.

         Our agreements with various suppliers of the veterinary medical devices
require us to meet minimum annual sales levels to maintain our position as the
exclusive distributor of these devices. We may not meet these minimum sales
levels in the future, and maintain exclusivity over the distribution and sale of
these products. If we are not the exclusive distributor of these products,
competition may increase.

WE DEPEND ON PARTNERS IN OUR RESEARCH AND DEVELOPMENT ACTIVITIES. IF OUR CURRENT
PARTNERSHIPS AND COLLABORATIONS ARE NOT SUCCESSFUL, WE MAY NOT BE ABLE TO
DEVELOP OUR TECHNOLOGIES OR PRODUCTS.

         For various of our proposed products, we are dependent on collaborative
partners to successfully and timely perform research and development activities
on our behalf. These collaborative partners may not complete research and
development activities on our behalf in a timely fashion, or at all. If our
collaborative partners fail to complete research and development activities, or
fail to complete them in a timely fashion, our ability to develop technologies
and products will be impacted negatively and our revenues will decline.

WE DEPEND ON KEY PERSONNEL FOR OUR FUTURE SUCCESS. IF WE LOSE OUR KEY PERSONNEL
OR ARE UNABLE TO ATTRACT AND RETAIN ADDITIONAL PERSONNEL, WE MAY BE UNABLE TO
ACHIEVE OUR GOALS.

         Our future success is substantially dependent on the efforts of our
senior management and scientific team. The loss of the services of members of
our senior management or scientific staff may significantly delay or prevent the
achievement of product development and other business objectives. Because of the
specialized scientific nature of our business, we depend substantially on our
ability to attract and retain qualified scientific and technical personnel.
There is intense competition among major pharmaceutical and chemical companies,
specialized biotechnology firms and universities and other research institutions
for qualified personnel in the areas of our activities. If we lose the services
of, or fail to recruit, key scientific and technical personnel, the growth of
our business could be substantially impaired.


                                      -9-
   11


WE MAY FACE PRODUCT RETURNS AND PRODUCT LIABILITY LITIGATION AND THE EXTENT OF
OUR INSURANCE COVERAGE IS LIMITED. IF WE BECOME SUBJECT TO PRODUCT LIABILITY
CLAIMS RESULTING FROM DEFECTS IN OUR PRODUCTS, WE MAY FAIL TO ACHIEVE MARKET
ACCEPTANCE OF OUR PRODUCTS AND OUR BUSINESS COULD BE HARMED.

         The testing, manufacturing and marketing of our current products as
well as those currently under development entail an inherent risk of product
liability claims and associated adverse publicity. Following the introduction of
a product, adverse side effects may be discovered. Adverse publicity regarding
such effects could affect sales of our other products for an indeterminate time
period. To date, we have not experienced any material product liability claims,
but any claim arising in the future could substantially harm our business.
Potential product liability claims may exceed the amount of our insurance
coverage or may be excluded from coverage under the terms of the policy. We may
not be able to continue to obtain adequate insurance at a reasonable cost, if at
all. In the event that we are held liable for a claim against which we are not
indemnified or for damages exceeding the $10 million limits of our insurance
coverage or which results in significant adverse publicity against us, we may
lose revenue and fail to achieve market acceptance.

WE MAY BE HELD LIABLE FOR THE RELEASE OF HAZARDOUS MATERIALS, WHICH COULD RESULT
IN EXTENSIVE COSTS WHICH WOULD HARM OUR BUSINESS.

         Our products and development programs involve the controlled use of
hazardous and biohazardous materials, including chemicals, infectious disease
agents and various radioactive compounds. Although we believe that our safety
procedures for handling and disposing of such materials comply with the
standards prescribed by applicable local, state and federal regulations, we
cannot completely eliminate the risk of accidental contamination or injury from
these materials. In the event of such an accident, we could be held liable for
any fines, penalties, remediation costs or other damages that result. Our
liability for the release of hazardous materials could exceed our resources,
which could lead to a shut down of our operations. In addition, we may incur
substantial costs to comply with environmental regulations as we expand our
manufacturing capacity.

WE EXPECT TO EXPERIENCE VOLATILITY IN OUR STOCK PRICE, WHICH MAY AFFECT OUR
ABILITY TO RAISE CAPITAL IN THE FUTURE OR MAKE IT DIFFICULT FOR INVESTORS TO
SELL THEIR SHARES.

         The securities markets have from time to time experienced significant
price and volume fluctuations that are unrelated to the operating performance of
particular companies. The market prices of securities of many publicly-held
biotechnology companies have in the past been, and can in the future be expected
to be, especially volatile. For example, in the last twelve months our stock
price has ranged from a low of $0.59375 to a high of $6.00. Fluctuations in the
trading price or liquidity of our common stock may adversely affect our ability
to raise capital through future equity financings. Factors that may have a
significant impact on the market price and marketability of our common stock
include:

         o        announcements of technological innovations or new products by
                  us or by our competitors;

         o        our quarterly operating results;

         o        releases of reports by securities analysts;

         o        developments or disputes concerning patents or proprietary
                  rights;

         o        regulatory developments;

         o        developments in our relationships with collaborative partners;

         o        changes in regulatory policies;

         o        litigation;

         o        economic and other external factors; and

         o        general market conditions.


                                      -10-
   12


         In the past, following periods of volatility in the market price of a
company's securities, securities class action litigation has often been
instituted. If a securities class action suit is filed against us, we would
incur substantial legal fees and our management's attention and resources would
be diverted from operating our business in order to respond to the litigation.

IF WE FAIL TO MEET NASDAQ NATIONAL MARKET LISTING REQUIREMENTS, OUR COMMON STOCK
WILL BE DELISTED AND BECOME ILLIQUID.

         Our common stock is currently listed on the Nasdaq National Market.
Nasdaq has requirements we must meet in order to remain listed on the Nasdaq
National Market. If we continue to experience losses from our operations or we
are unable to raise additional funds, we might not be able to maintain the
standards for continued quotation on the Nasdaq National Market, including a
minimum bid price requirement of $1.00. If the minimum bid price of our common
stock were to remain below $1.00 for 30 consecutive trading days, or if we were
unable to continue to meet Nasdaq's standards for any other reason, our common
stock could be delisted from the Nasdaq National Market.

         If as a result of the application of these listing requirements, our
common stock were delisted from the Nasdaq National Market, our stock would
become harder to buy and sell. Further, our stock could be subject to what are
known as the "penny stock" rules. The penny stock rules place additional
requirements on broker-dealers who sell or make a market in such securities.
Consequently, if we were removed from the Nasdaq National Market, the ability or
willingness of broker-dealers to sell or make a market in our common stock might
decline. As a result, the ability for investors to resell shares of our common
stock could be adversely affected.

THE COMMON STOCK SOLD IN THIS OFFERING WILL INCREASE THE SUPPLY OF OUR COMMON
STOCK ON THE PUBLIC MARKET, WHICH MAY CAUSE OUR STOCK PRICE TO DECLINE.

         The sale into the public market of the common stock to be sold in this
offering could adversely affect the market price of our common stock. Most of
our shares of common stock outstanding are eligible for immediate and
unrestricted sale in the public market at any time. Once the registration
statement of which this prospectus forms a part is declared effective, the
4,573,000 shares of common stock covered by this prospectus will be eligible for
immediate and unrestricted resale into the public market. The presence of these
additional shares of common stock in the public market may further depress our
stock price.

                                 USE OF PROCEEDS

         Heska will not receive any of the proceeds from the sale of the shares
offered by this prospectus. All proceeds from the sale of the shares offered
hereby will be for the account of the selling stockholders, as described below.
See "Selling Stockholders" and "Plan of Distribution."


                              SELLING STOCKHOLDERS

         The following table sets forth as of February 9, 2001, the name of each
of the selling stockholders, the number of shares of common stock that each
selling stockholder owns, the number of shares of common stock owned by each
selling stockholder that may be offered for sale from time to time by this
prospectus, and the number of shares of common stock to be held by each selling
stockholder assuming the sale of all the common stock offered hereby.


                                      -11-
   13


         Some of the selling stockholders may distribute their shares, from time
to time, to their limited and/or general partners, who may sell shares pursuant
to this prospectus. Each selling stockholder may also transfer shares owned by
him by gift, and upon any such transfer the donee would have the same right of
sale as the selling stockholder.

         The shares being offered by the selling stockholders were acquired in
connection with a private placement on February 6, 2001. Except as set forth
below, none of the selling stockholders has had a material relationship with us
within the past three years other than as a result of the ownership of our
common stock. We may amend or supplement this prospectus from time to time to
update the disclosure set forth herein.



                                                                                          NUMBER OF
                                                                                           SHARES
                                                             SHARES BENEFICIALLY OWNED      BEING       SHARES BENEFICIALLY OWNED
NAME OF SELLING STOCKHOLDER                                       PRIOR TO OFFERING(1)     OFFERED        AFTER OFFERING(1)(2)
---------------------------                                  -------------------------    ----------    -------------------------
                                                               NUMBER        PERCENT                     NUMBER          PERCENT
                                                             ---------       ---------                  ---------        -------
                                                                                                          
State of Wisconsin Investment Board ...................       6,468,000       16.73%      1,000,000       5,468,000      14.15%
Charter Ventures II, L.P.(3) ..........................       6,206,924       16.06%      1,000,000       5,206,924      13.47%
Lombard Odier & Cie(4).................................       2,774,200        7.18%      1,000,000       1,774,200       4.59%
Edith W. Martin, Ph.D.(5) .............................          38,500           *          36,000           2,500          *
National Federation of Independent Business (NFIB)
  Corp Acct(6) ........................................         172,000           *          77,000          95,000          *
Norwalk Employees' Pension Plan(6) ....................         258,000           *         108,000         150,000          *
Public Employee Retirement System of Idaho(6) .........       1,135,000        2.94%        385,000         750,000       1.94%
City of Stamford Firemen's Pension Fund(6) ............         138,000           *          38,000         100,000          *
Lazar Foundation(6) ...................................          63,000           *          38,000          25,000          *
Roanoke College(6) ....................................         138,000           *          38,000         100,000          *
HBL Charitable Unitrust(6) ............................          38,000           *          38,000              --         --
Psychology Associates(6) ..............................          58,000           *          38,000          28,000          *
Peter Looram(6) .......................................          73,000           *          38,000          35,000          *
Mary C. Anderson(6) ...................................          77,000           *          77,000              --          *
Murray Capital, LLC(6) ................................          38,000           *          38,000              --         --
The Meehan Investment Partnership I, L.P.(6) ..........          98,000           *          58,000          40,000          *
Domenic J. Mizio(6) ...................................         132,000           *          77,000          55,000          *
Theeuwes Family Trust, Felix Theeuwes Trustee(6) ......          77,000           *          77,000              --         --
Wells Family LLC(6) ...................................         231,000           *         231,000              --         --
Albert L. Zesiger(6) ..................................         222,000           *         115,000         107,000          *
Barrie Ramsay Zesiger(6) ..............................         133,000           *          58,000          75,000          *
John J. & Catherine H. Kayola(6) ......................           8,000           *           8,000              --         --


----------

*   Represents less than 1% of our common stock.

(1) Based on 38,655,758 shares outstanding as of February 9, 2001.

(2) Assumes that each selling stockholder sells all shares registered under this
    registration statement. However, to our knowledge, there are no agreements,
    arrangements or understandings with respect to the sale of any of our common
    stock, and each selling stockholder may decide not to sell his shares that
    are registered under this registration statement.

(3) Represents 3,386,510 shares and options to purchase 1,000 shares of our
    common stock held by Charter Ventures and 2,818,414 shares and options to
    purchase 1,000 shares of our common stock held by Charter Ventures II, L.P.,
    with respect to which Mr. A. Barr Dolan, one of our directors, disclaims
    beneficial ownership except to the extent of his proportionate share
    therein. Mr. Dolan is a general partner of each of Charter Ventures and
    Charter Ventures II, L.P., and may be deemed a beneficial owner of the
    shares held by such entities because of shared voting power with respect to
    such shares.


                                      -12-
   14
(4) Shares listed consist of 2,755,000 shares held as custodian for the Lombard
    Odier Nutrition Fund, over which Lombard Odier & Cie and Lombard Odier Fund
    Managers S.A. share voting and dispositive power, and 19,200 shares held for
    the benefit of private and institutional clients. Such clients have the
    right to receive or the power to direct the receipt of dividends from, or
    the proceeds from the sale of, such shares and retain sole voting power with
    respect to such shares.


(5) Dr. Edith Martin is one of our directors. The amount of shares beneficially
    owned includes 2,500 shares of common stock issuable upon exercise of stock
    options currency exercisable with 60 days of February 9, 2001.

(6) Zesiger Capital Group LLC acted as the agent and attorney-in-fact for this
    selling stockholder in connection with the stockholder's acquisition from us
    of the shares offered by this selling stockholder under this prospectus.
    Zesiger Capital Group LLC is an investment adviser registered with the
    Securities and Exchange Commission under the Investment Advisers Act of
    1940. This selling stockholder is an advisory client of Zesiger Capital
    Group LLC, and the shares offered by this selling stockholder under this
    prospectus are held in a discretionary client account managed by Zesiger
    Capital Group LLC. Zesiger Capital Group LLC disclaims beneficial ownership
    of these shares.

                              PLAN OF DISTRIBUTION

         Heska is registering 4,573,000 shares of Common Stock, par value of
$0.001 per share on behalf of certain selling stockholders. Heska will receive
no proceeds from this offering. The shares may be offered by certain
stockholders of Heska or by pledgees, donees, transferees or other successors in
interest that receive such shares as a gift, partnership distribution or other
non-sale related transfer. The shares were originally issued by Heska in
connection with the Stock Purchase Agreement between Heska and the selling
stockholders, dated February 1, 2001 (the "Stock Purchase Agreement"). The
shares are being registered by Heska pursuant to the Stock Purchase Agreement.
The shares were issued pursuant to exemptions from the registration requirements
of the Securities Act, provided by Section 4(2) thereof.

         The selling stockholders will act independently of Heska in making
decisions with respect to the timing, manner and size of each sale. The selling
stockholders may sell the shares on the Nasdaq National Market, or otherwise, at
prices and under terms then prevailing or at prices related to the then current
market price, at varying prices or at negotiated prices. The shares may be sold,
without limitation, by one or more of the following means of distribution: (a) a
block trade in which the broker-dealer so engaged will attempt to sell such
shares as agent, but may position and resell a portion of the block as principal
to facilitate the transaction; (b) purchases by a broker-dealer as principal and
resale by such broker-dealer for its own account pursuant to this prospectus;
(c) an over-the-counter distribution in accordance with the rules of the Nasdaq
National Market; (d) ordinary brokerage transactions and transactions in which
the broker solicits purchasers; and (e) in privately negotiated transactions. To
the extent required, this prospectus may be amended and supplemented from time
to time to describe a specific plan of distribution.

         In connection with distributions of the shares or otherwise, the
selling stockholders may enter into hedging transactions with broker-dealers or
other financial institutions. In connection with such transactions,
broker-dealers or other financial institutions may engage in short sales of the
shares in the course of hedging the positions they assume with selling
stockholders. The selling stockholders may also sell the shares short and
redeliver the shares to close out such short positions. The selling stockholders
may also enter into option or other transactions with broker-dealers or other
financial institutions which require the delivery to such broker-dealer or other
financial institution of the shares, which shares such broker-dealer or other
financial institution may resell or otherwise transfer pursuant to this
prospectus (as supplemented or amended to reflect such transaction). The selling
stockholders may also pledge the shares to a broker-dealer or other financial
institution, and, upon a default, such broker-dealer or other financial
institution, may effect sales of the pledged shares pursuant to this prospectus
(as supplemented or amended to reflect such transaction). In addition, any
shares that qualify for sale pursuant to Rule 144 may, at the option of the
holder thereof, be sold under Rule 144 rather than pursuant to this prospectus.

         Any broker-dealer participating in such transactions as agent may
receive commissions from the selling stockholders and/or purchasers of the
shares (and, if it acts as agent for the purchaser of such shares, from such
purchaser). Usual and customary brokerage fees will be paid by the selling
stockholders. Broker-dealers


                                      -13-
   15

may agree with the selling stockholders to sell a specified number of shares at
a stipulated price per share, and, to the extent such a broker-dealer is unable
to do so acting as agent for the selling stockholders, to purchase as principal
any unsold shares at the price required to fulfill the broker-dealer commitment
to the selling stockholders. Broker-dealers who acquire shares as principal may
thereafter resell such shares from time to time in transactions (which may
involve cross and block transactions and which may involve sales to and through
other broker-dealers, including transactions of the nature described above) in
the over-the-counter market, in negotiated transactions or otherwise at market
prices prevailing at the time of sale or at negotiated prices, and in connection
with such resales, may pay to or receive from the purchasers of such shares
commissions computed as described above. Such broker-dealers and any other
participating broker-dealers or the selling stockholders may be deemed to be
"underwriters" within the meaning of Section 2(11) of the Securities Act in
connection with such sales and any such commission, discount or concession may
be deemed to be underwriting discounts or commissions under the Securities Act.
Because the selling stockholders may be deemed to be an underwriter under
Section 2(11) of the Securities Act, the selling stockholders will be subject to
the prospectus delivery requirements of the Securities Act.

         To comply with the securities laws of certain states, if applicable,
the shares will be sold in such jurisdictions only through registered or
licensed brokers or dealers. In addition, in certain states the shares may not
be sold unless they have been registered or qualified for sale in the applicable
state or an exemption from the registration or qualification requirement is
available and is complied with.

         Under applicable rules and regulations under the Exchange Act, any
persons engaged in the distribution of the shares may not simultaneously engage
in market making activities with respect to our common stock for a period of two
business days prior to the commencement of such distribution. In addition and
without limiting the foregoing, each selling stockholder will be subject to
applicable provisions of the Exchange Act and the associated rules and
regulations thereunder, including, without limitation, Regulation M, which
provisions may limit the timing of purchases and sales of shares of our common
stock by the selling stockholders. Heska will make copies of this prospectus
available to the selling stockholders and have informed them of the need for
delivery of copies of this prospectus to purchasers at or prior to the time of
any sale of the shares. Heska assumes no obligation to so deliver copies of this
prospectus or any related prospectus supplement.

         At the time a particular offer of shares is made, if required, a
prospectus supplement will be distributed that will set forth the number of
shares being offered and the terms of the offering, including the name of any
underwriter, dealer or agent, the purchase price paid by any underwriter, any
discount, commission and other item constituting compensation, any discount,
commission or concession allowed or reallowed or paid to any dealer, and the
proposed selling price to the public.

         The selling stockholders will be responsible for any fees,
disbursements and expenses of any counsel for the selling stockholders. All
other expenses incurred in connection with the registration of the shares,
including printer's and accounting fees and the fees, disbursements and expenses
of counsel for Heska will be borne by us up to a certain amount. Commissions and
discounts, if any, attributable to the sales of the shares will be borne by the
selling stockholders. The selling stockholders may agree to indemnify any
broker-dealer that participates in transactions involving sales of the shares
against certain liabilities, including liabilities arising under the Securities
Act. Heska will indemnify the selling stockholders against claims arising out of
any untrue statement of a material fact contained in this Registration Statement
or any omission to state therein a material fact necessary in order to make the
statement made therein not misleading.

         Heska has undertaken to keep a Registration Statement of which this
prospectus constitutes a part effective until the earlier of the disposition of
the securities offered hereby or two years measured from the


                                      -14-
   16


effective date of this Registration Statement. After such period, if we choose
not to maintain the effectiveness of the Registration Statement of which this
prospectus constitutes a part, the securities issuable offered hereby may not be
sold, pledged, transferred or assigned, except in a transaction which is exempt
under the provisions of the Securities Act of pursuant to an effective
registration statement thereunder.

                                  LEGAL MATTERS

         Certain legal matters relating to the validity of the securities
offered hereby will be passed upon for Heska by Wilson Sonsini Goodrich &
Rosati, Professional Corporation, San Francisco, California.

                                     EXPERTS

         The financial statements incorporated in this prospectus by reference
to the Annual Report on Form 10-K of Heska for the year ended December 31, 1999
have been so incorporated in reliance on the report of Arthur Andersen LLP,
independent public accountants, given on the authority of said firm as experts
in giving said reports.



                                      -15-
   17


         PROSPECTIVE INVESTORS MAY RELY ONLY ON THE INFORMATION CONTAINED IN
THIS PROSPECTUS. NEITHER HESKA NOR ANY SELLING STOCKHOLDERS HAS AUTHORIZED
ANYONE TO PROVIDE PROSPECTIVE INVESTORS WITH INFORMATION DIFFERENT FROM THAT
CONTAINED IN THIS PROSPECTUS. THIS PROSPECTUS IS NOT AN OFFER TO SELL NOR IS IT
SEEKING AN OFFER TO BUY THE SHARES IN ANY JURISDICTION WHERE THE OFFER OR SALE
IS NOT PERMITTED. THE INFORMATION CONTAINED IN THIS PROSPECTUS IS CORRECT ONLY
AS OF THE DATE OF THIS PROSPECTUS, REGARDLESS OF THE TIME OF THE DELIVERY OF
THIS PROSPECTUS OR ANY SALE OF THE SHARES.








                                HESKA CORPORATION

                                4,573,000 SHARES
                                  COMMON STOCK

                                   ----------

                                   PROSPECTUS

                                   ----------



                                 _________, 2001


   18



                                     PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION

         The Company will pay all expenses incident to the offering and sale to
the public of the shares being registered other than any commissions and
discounts of underwriters, dealers or agents and any transfer taxes. Such
expenses are set forth in the following table. All of the amounts shown are
estimates except for the Securities and Exchange Commission registration fee.



                                       
SEC Registration Fee ..............       $ 1,358
Accounting fees and expenses ......        15,000
Legal fees and expenses ...........        20,000
Miscellaneous .....................           142
                                          -------
       Total ......................       $36,500
                                          =======


ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS

         Section 145 of the Delaware General Corporation Law allows for the
indemnification of officers, directors and any corporate agents in terms
sufficiently broad to indemnify such persons under certain circumstances for
liabilities (including reimbursement for expenses incurred) arising under the
Securities Act. Our certificate of incorporation and our bylaws provide for
indemnification of our directors, officers, employees and other agents to the
extent and under the circumstances permitted by the Delaware General Corporation
Law. We have also entered into agreements with our directors and executive
officers that require Heska, among other things, to indemnify them against
certain liabilities that may arise by reason of their status or service as
directors and executive officers to the fullest extent permitted by Delaware
law. We have also purchased directors and officers liability insurance, which
provides coverage against certain liabilities including liabilities under the
Securities Act.

ITEM 16. EXHIBITS

                                  EXHIBIT INDEX

EXHIBIT
 NUMBER       NOTES       DESCRIPTION
   5.1                  Opinion of Wilson Sonsini Goodrich & Rosati,
                        Professional Corporation

  10.42        (1)      Stock Purchase Agreement dated February 1, 2001

  23.1                  Consent of Wilson Sonsini Goodrich & Rosati,
                        Professional Corporation (included in Exhibit 5.1)

  23.2                  Consent of Arthur Andersen LLP, independent accountants

  24.1                  Power of Attorney (contained on Page II-3)
----------

NOTES

(1) Filed with Registrant's Current Report on Form 8-K on February 7, 2001.

ITEM 17. UNDERTAKINGS

(a)      The undersigned Registrant hereby undertakes:

         (1) To file, during any period in which offers or sales are being made,
a post-effective amendment to this Registration Statement (i) to include any
prospectus required by Section 10(a)(3) of the


                                      II-1
   19


Securities Act of 1933, as amended (the "Securities Act:"), (ii) to reflect in
the prospectus any facts or events arising after the effective date of the
registration statement (or the most recent post-effective amendment thereof)
which, individually or in the aggregate, represent a fundamental change in the
information set forth in the registration statement. Notwithstanding the
foregoing, any increase or decrease in volume of securities offered (if the
total dollar value of securities offered would not exceed that which was
registered) and any deviation from the low or high end of the estimated maximum
offering range may be reflected in the form of prospectus filed with the
Securities and Exchange Commission pursuant to Rule 424(b) if, in the aggregate,
the changes in volume and price represent no more than a 20 percent change in
the maximum aggregate offering price set forth in the "Calculation of
Registration Fee" table in the effective registration statement, and (iii) to
include any material information with respect to the plan of distribution not
previously disclosed in the Registration Statement or any material change to
such information in the Registration Statement; provided, however, that
paragraphs (a)(1)(i) and (a)(1)(ii) above do not apply if the information
required to be included in a post-effective amendment by those paragraphs is
contained in the periodic reports filed by the Registrant pursuant to Section 13
or Section 15(d) of the Securities Exchange Act of 1934 (the "Exchange Act")
that are incorporated by reference into this Registration Statement.

         (2) That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
Registration Statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

         (3) To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering.

(b)      The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act that is incorporated by reference in the Registration Statement
shall be deemed to be a new Registration Statement relating to the securities
offered therein, and the offering of such securities at that time shall be
deemed to be the initial bona fide offering thereof.

(c)      Insofar as indemnification for liabilities arising under the Securities
Act may be permitted to directors, officers and controlling persons of the
Registrant pursuant to the foregoing provisions, or otherwise, the Registrant
has been advised that in the opinion of the Securities and Exchange Commission
such indemnification is against public policy as expressed in the Securities Act
and is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a director, officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Securities Act and will be governed by the final
adjudication of such issue.

(d)      The undersigned Registrant hereby undertakes that:

         (1) for purposes of determining any liability under the Securities Act,
the information omitted from the form of prospectus filed as part of this
registration statement in reliance upon Rule 430A and contained in a form of
prospectus filed by the Registrant pursuant to Rule 424(b)(1) or (4) or 497(h)
under the Securities Act shall be deemed to be part of this Registration
Statement as of the time it was declared effective.

         (2) for the purpose of determining liability under the Securities Act,
each post-effective amendment that contains a form of prospectus shall be deemed
to be a new registration statement relating to the securities offered therein,
and the offering of such securities at that time shall be deemed to be the
initial bona fide offering thereof.


                                      II-2
   20



                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-3 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Fort Collins, State of Colorado, on February 14,
2001.

                                           HESKA CORPORATION


                                           By: /s/ Robert B. Grieve
                                              ---------------------------
                                              Robert B. Grieve
                                              Chief Executive Officer and
                                              Chairman of the Board

                                POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Robert B. Grieve, Ronald L. Hendrick and
Michael A. Bent his or her attorney-in-fact, with the power of substitution, for
him or her in any and all capacities, to sign any amendment to this Registration
Statement on Form S-3, and to file the same, with exhibits thereto and other
documents in connection therewith, with the Securities and Exchange Commission,
granting to said attorney-in-fact full power and authority to do and perform
each and every act and thing requisite and necessary to be done in connection
therewith, as fully to all intents and purposes as he might or could do in
person, hereby ratifying and confirming all that said attorney-in-fact, or his
substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed below by the following persons on behalf
of the Registrant on February 14, 2001.




       SIGNATURE                            TITLE
       ---------                            -----
                                
/s/ Robert B. Grieve               Chief Executive Officer (Principal Executive
-------------------------          Officer) and Chairman of the Board
Robert B. Grieve


/s/ Ronald L. Hendrick             Chief Financial Officer (Principal Financial
-------------------------          and Accounting Officer)
Ronald L. Hendrick


/s/ Fred M. Schwarzer              Director
-------------------------
Fred M. Schwarzer


/s/ A. Barr Dolan                  Director
-------------------------
A. Barr Dolan


/s/ Lyle A. Hohnke                 Director
-------------------------
Lyle A. Hohnke




                                      II-3
   21





       SIGNATURE                   TITLE
       ---------                   -----
                                


/s/ William A. Aylesworth          Director
-------------------------
William A. Aylesworth


/s/ Lynnor B. Stevenson            Director
-------------------------
Lynnor B. Stevenson


/s/ Edith W. Martin                Director
-------------------------
Edith W. Martin



/s/ John F. Sasen, Sr.             Director
-------------------------
John F. Sasen, Sr.


   22



                                INDEX TO EXHIBITS




EXHIBIT
 NUMBER       NOTES      DESCRIPTION
-------       -----      ------------
                   
  5.1                    Opinion of Wilson Sonsini Goodrich & Rosati,
                         Professional Corporation

 10.42         (1)       Stock Purchase Agreement dated February 1, 2001

 23.1                    Consent of Wilson Sonsini Goodrich & Rosati,
                         Professional Corporation (included in Exhibit 5.1)

 23.2                    Consent of Arthur Andersen LLP, independent accountants

 24.1                    Power of Attorney (contained on Page II-3)

----------

NOTES

(1) Filed with Registrant's Current Report on Form 8-K on February 7, 2001.