Exhibit 99.1

VMSI Expects Higher Sales and EPS

    TUCSON, Ariz.--(BUSINESS WIRE)--July 8, 2004--Ventana Medical
Systems Inc. (NASDAQ:VMSI) announced today preliminary second quarter
sales of approximately $42 million are higher than expected and were
driven by strong growth in both instrument and consumable sales. As a
result, the company expects to report fully diluted earnings per share
in a range of $0.33 to $0.35, or $0.05 to $0.07 more than the current
consensus estimate and $0.13 to $0.15 better than the second quarter
of last year.
    The company will discuss the full second quarter financial and
operating results and their impact on overall 2004 projections during
its regularly scheduled second quarter conference call.

    Conference Call

    Ventana will hold a conference call on Friday, July 16, 2004, at
10 a.m. EST to discuss the company's full second quarter financial and
operating results. The call can be accessed via the Internet live and
as a replay at www.viavid.net.
    Ventana develops, manufactures, and markets instrument/reagent
systems that automate slide preparation and staining in clinical
histology and drug discovery laboratories worldwide. Ventana's
clinical systems are important tools used in the diagnosis and
treatment of cancer and infectious diseases. Ventana's drug discovery
systems are used to accelerate the discovery of new drug targets and
evaluate the safety of new drug compounds.
    Any statements made about the company's anticipated financial
results are forward-looking statements subject to risks and
uncertainties, such as the risks inherent in the development,
manufacturing, marketing and sale of medical products, competitive
factors, general economic conditions, legal disputes, and government
actions as more fully described in Ventana's Annual Report on Form
10-K for the year ended Dec. 31, 2003. Actual results may differ
materially from anticipated results.
    Visit the Ventana Medical Systems Inc. Web site at
www.ventanamed.com.
    The Molecular Discovery Systems Division has its own Web site at
www.ventanadiscovery.com.

    CONTACT: Ventana Medical Systems, Tucson
             Christopher M. Gleeson, 520-229-3787
             Nick Malden, 520-229-3857