Oesophago-gastro-duodenoscopy was successfully performed in 196 of 208 patients admitted with haematemesis or melaena, or both. A precise visual diagnosis was made in 80% of all patients and in 96% of those where the final diagnosis lay within the oesophagus, stomach, and first two parts of the duodenum. Bleeding oesophagitis was more common and bleeding duodenal ulcer less common than in other series using mainly radiology. Altogether, 26% of all patients with endoscopically-proved duodenal ulcers were bleeding from another site, and 15.4% of all patients had more than one lesion. This fact, and inability to detect surface lesions limits the value of acute barium radiology, which was performed in only 81 patients. Accurate diagnosis should lead to better understanding of individual lesions and more rational management of individual patients. Where a good service is available oesophago-gastro-duodenoscopy should be performed on all bleeding patients within 24 hours of admission.