The appropriateness of long-term cimetidine prescribing was evaluated retrospectively in 243 outpatients. Criteria defining appropriate indications for the use of cimetidine for longer than eight weeks were established. Of the 243 patients surveyed, 115 (47 percent) were considered to be inappropriately receiving long-term cimetidine, either because they had never been objectively studied radiographically or endoscopically (23 percent) or had negative results before initiation of therapy (24 percent). Risk factors known to be associated with recurrent peptic ulcer disease were reviewed. Patients fulfilling criteria for appropriate long-term cimetidine usage had a greater prevalence of risk factors compared to the nonjustifiable group. Of particular interest, individuals considered appropriate for long-term therapy were very likely to have had a gastrointestinal bleeding episode prior to beginning therapy (52 percent for gastric ulcer, 8 percent for the nonjustifiable group). This increased prevalence of gastrointestinal hemorrhage may be due to the inherent nature of peptic ulcer disease or a result of physicians selecting affected individuals who may benefit from long-term treatment. Eliminating inappropriate usage of long-term cimetidine in conjunction with a thorough evaluation of risk factors for recurrent ulcer disease can be useful in selecting those individuals most likely to benefit from long-term cimetidine therapy.