The mortality, causes of death, and the factors that are influencing deaths from bleeding acute and chronic peptic ulcers were evaluated retrospectively. During a 2-year period (1986-87) 272 patients were endoscoped for acute gastrointestinal hemorrhage and were found to have bled from a peptic ulcer (chronic gastric ulcers, 90; chronic duodenal ulcers, 114; acute gastroduodenal ulcers, 66; stomal ulcers, 2). The overall mortality was 9.6% (n = 26) (gastric ulcers, 6.7%; duodenal ulcers, 11.4%; acute ulcers, 10.6%). Statistically significant factors adversely affecting prognosis for gastric ulcer were re-bleeding, need for operation and serious intercurrent illness; for duodenal ulcer were units of transfused blood, re-bleeding, signs of recent hemorrhage at endoscopy, need for operation, and serious intercurrent illness; and for acute ulcer were increasing age, shock, units of transfused blood, re-bleeding, and serious intercurrent illness. Multivariate analysis was only attempted for duodenal ulcers because of sample sizes; it suggested that active bleeding or visible vessel at endoscopy, re-bleeding, and serious intercurrent illness were independent factors for mortality. From this study it is apparent that the major determinants of a fatal outcome in bleeding peptic ulcer diseases were serious intercurrent illness and re-bleeding. As it must be anticipated that patients with these particular problems are at high risk of a poor outcome, it follows that it is important they have access to skilled treatment as provided by a specialist team in an intensive care ward. It also follows that every effort should be made to keep ulcers in remission to free the ulcer patient of potentially lethal complications.