The background, evolution, and current status of drug utilization review (DUR) in the developed countries is reviewed. DUR is defined as "an authorized, structured, and continuing program that reviews, analyzes, and interprets patterns of drug usage in a given health care delivery system against predetermined standards". DUR program has been developed to improve the quality of pharmaceutical care and promote cost-effectiveness of drug therapy. DUR provides feedback to physicians on the possibility of adverse effect of their prescription to the patients. DUR is classified retrospective, prospective, and concurrent according to the direction of implementation. Information systems and databases are essential to perform DUR program and DUR study. They could be used to enable physicians to develop more rational prescribing rules from population data that would improve the quality of pharmaceutical care.