To assess the type of information requested of a pharmaceutical manufacturer, re quests received over a 12 month period in the Professional Services Department of Sterling Drug Inc were reviewed. To compare drug information services of Sterling Drug with those of pharmacist-operated drug information centers (DICs), requests were classified as to the nature of the question, category of requestor, and patient specificity. Questions regarding dosage or administration, drug identification, and adverse drug events were common in both DICs and industry. At Sterling Drug Inc the largest number of requests were for literature reprints or physician drug samples and dosage or administration. This contrasts with hospital-based DICs, where the largest number of requests pertained to therapeutic use and drug efficacy or adverse drug events. At Sterling and DICs few questions pertained to pharmacology, toxicol ogy or poisoning, and pharmacokinetics. Physicians comprised the largest group of requestors in DICs. Professional and support staffing of DIC and industry drug information practice are compared. Staffing by PharmDs and RPhs was practically identical for drug information services regardless of whether the practice site was industry or DIC.