Abstract 1. 1. At the Lahey Clinic 707 patients with gastric ulcer were treated surgically. The incidence of malignant disease was 13.2 per cent. 2. 2. There were no significant differences in sex, age, or duration of symptoms between patients with benign and those with malignant ulcer. 3. 3. The location and size of benign and of malignant ulcers differed slightly. 4. 4. The treatment of patients who have uncomplicated gastric ulcer should consist of hospitalization and a trial of medical therapy. Failure of the ulcer to heal completely or recurrence are indications for prompt surgical intervention. 5. 5. The surgical treatment recommended is excision of the ulcer by a moderate partial gastrectomy. 6. 6. The mortality for our entire series was 2.1 per cent.