Upper gastrointestinal endoscopy was performed in 106 of 204 Chinese patients with intact abdominal aortic aneurysms, ninety-seven for screening and nine for gastrointestinal bleeding or pain. Peptic disease was discovered in 38 patients: 12 duodenal ulcers, 12 gastric ulcers, four duodenal and gastric ulcers, three duodenitis, three gastritis and four previously operated for ulcers. The eight patients who bled before aneurysmectomy all had gastric ulcers; four required emergency operation and two died. Only two patients bled from duodenal ulcers, both after aneurysmectomy and one died. Excluding gastritis and duodenitis, peptic ulcer was found in 26.4% of patients with abdominal aortic aneurysms. Half of these ulcers were gastric ulcers and 50% of them bled before aneurysmectomy. Duodenal ulcers tend to remain asymptomatic before operation and two of 12 (16.7%) bled postoperatively. The risk of bleeding for ulcers associated with aneurysms was 10 of 28 (35.7%) ulcers. The result of this uncontrolled study suggests that routine endoscopic screening should be used in all patients with aortic aneurysms and early surgery should be offered for gastric ulcers.