This report is submitted to present the current findings of the follow-up studies of 493 Billroth I type of subtotal gastric resections done over a period of seven and one-half years (1948-1955). The clinical studies reported here are supplemented by experimental data comparing the results of the Billroth I and the Billroth II types of operation when there is an abnormally high stress of acid-peptic secretion. I. CLINICAL DATA The operative procedures were performed in the affiliated hospitals of the University of Washington School of Medicine. The operations were done by the members of the surgical faculty or residents in surgery trained by them. Among the total of 493 Billroth I gastrectomies, 42 were carried out for malignant disease. Since our interest in this presentation is directed primarily toward the treatment of benign lesions, the patients with malignancy will be eliminated from further consideration, except for some brief comments. During