Most surgeons are unaware that patients with pulmonary emphysema have an inordinately high incidence of peptic ulceration and that these ulcers are of a peculiarly complicated and resistant nature. This paper is a review of the incidence of peptic ulcer in our own Emphysema Registry, an investigation of gastric secretory activity in 20 patients with marked emphysema, and a study of pathogenic factors that may relate to the two conditions. The clinical implications of these findings are discussed. I. Frequency of Coexistence of the Diseases A. Incidence of Peptic Ulcer in Patients with Emphysema. —Green and Dundee,1 in 1952, found a 19% incidence of ulcer in both a clinical and an autopsy series of patients with proved emphysema. In a similar study, Flint and Warrack2 found a 21% incidence of peptic ulceration in 87 autopsy patients with proved emphysema, as compared with an incidence of 1.6% in a