Methods of assessing services and drug products provided by pharmaceutical vendors are discussed. Pharmacists must develop and justify criteria other than cost for selecting drug products to avoid pressures for basing product selection on price alone. Criteria used by many hospitals for evaluating pharmaceutical vendors are inspection of vendor facilities, availability of returned-goods policies, and availability of institution-specific services. Factors influencing a hospital's selection of a particular brand of drugs include product bioavailability, packaging, and labeling. A variety of hospital personnel should be allowed to participate in the evaluation of vendors and drug products to ensure accuracy and broad institutional support of the system. Guidelines for vendor representative activities in hospitals should be developed to promote the most effective use of vendor services and to prevent undesirable use of hospital personnel time. Effective criteria for evaluating pharmaceutical vendors and drug products saves time for the institution and ensures that drugs purchased are not associated with hidden expenses related to drug use.