The infrequency with which clinicians encounter primary tumors of the duodenum makes information regarding them rather meager. Our interest in this subject was stimulated by the opportunity to observe 3 patients, one with carcinoma, one with a carcinoid tumor, and one with a lymphangioma of the duodenum. Because of the interesting clinical, roentgenographic, and pathological findings in these cases, a review of other patients with duodenal tumors seen at our institution during the last 12 years was carried out in an attempt to collect further information which might prove helpful in evaluating individuals with lesions in this area of the intestinal tract. Material and Methods The records of all patients with a proved diagnosis of primary duodenal tumor seen at the University of Rochester Medical Center during the years 1950 through 1961 were reviewed. Only those patients in whom operation was performed and tissue obtained for histological examination were included.