The development and implementation of an active adverse drug reaction reporting program in a university teaching hospital is described. The progression from a solely voluntary system to a multidisciplinary program consisting of both voluntary and involuntary components is discussed. A total of 1,011 adverse reactions were reported between July 1, 1988 and July 22, 1992. The most common reaction reported was rash. Antibiotics were most commonly implicated in the reactions reported. As a single agent, digoxin was involved most frequently. Voluntary reporting by physicians, nurses, and pharmacists accounted for approximately 24% of the adverse reactions reported. Occurrence screening by the Quality Assurance department produced approximately 76% of the reports.