We studied mortality related to peptic ulcer bleed in a well defined cohort of patients in the month after the episode of peptic ulcer bleed. Our objective was to assess the contribution of peptic ulcer antecedents and other predictive factors on the risk of dying. The study cohort comprised 1,020 patients hospitalized for an episode of peptic ulcer bleed between January 1991 and March 1994 and identified in the General Practice Research Database in the United Kingdom. Six hundred twenty-three patients had no prior episode of peptic ulcer disease, and 384 had peptic ulcer antecedents; for 13 patients, information was not available. Forty-five patients died (mortality rate = 4.4 per 100 person-months; 95% confidence interval = 3.3-5.9) within 1 month of the peptic ulcer bleed. Patients with no peptic ulcer antecedent faced a greater risk of dying than patients with antecedents (relative risk = 3.0; 95% confidence interval = 1.2-7.1). Elderly patients, those undergoing surgery, and current users of acid-suppressing drugs or nonsteroidal antiinflammatory drugs all had an increased mortality risk. Patients presenting with their first-ever episode of peptic ulcer bleed have a higher case fatality rate than those with previous episodes of peptic ulcer.