From July 1, 1973 to June 30, 1976 789 patients admitted as upper gastrointestinal bleeders had endoscopies performed within 24 hours after preliminary resuscitation and preparation. More than one lesion was found in approximately 45% of the patients. Erosive hemorrhagic gastritis was the most common lesion, being present in 27.3–48.2% of the subjects (the latter percentage was found in those with a history of intake of both alcohol and ulcerogenic drugs). Gastric ulcer was the next most common lesion, present in 16.3–18.42%; the higher percentage represents the patients who were taking ulcerogenic drugs. The highest incidence of gastric ulcer (19.59%) or duodenal ulcer (10.5%) was among the patients in a group who had no apparent definite cause for the bleeding. A small number of patients had rare causes for the bleeding and in only a small percentage of the patients was the cause not diagnosed. These data suggest that early endoscopy is of diagnostic value in upper G.I. bleeders leading to prompt, lifesaving management and prevention of prolonged morbidity.