There has been some disagreement concerning the admittedly rare incidence of duodenal ulcer disease in children. Because of conflicting reports from other pediatrics centers, we have reviewed the records of all patients admitted to The Children's Hospital of Philadelphia in the past 20 years (1948 through 1967) in whom duodenal ulcer was diagnosed by x-ray, at operation or on postmortem examination (Table I). There were 27 children between the ages of 15 days and 15½ years, with well established duodenal ulcers. Six of these were female (22%). The age at presentation was scattered, but the majority were between 2 and 11 years of age. Presenting complaints were varied: gastrointestinal bleeding was most common in the younger age group, while abdominal pain, usually persistent and intermittent, was the most common symptom in the older children. The diagnosis of duodenal ulcer was made by x-ray examination in 22 patients and at operation in 2; and the ulcers were discovered only at autopsy in 3 children. All the ulcers were duodenal; the precise location was not specified in 9, but 11 were bulbar and 7 were postbulbar. Complications of the ulcer were noted in 9 patients. Perforation occurred in 7 patients, leading to death in 4 (all had disease of the central nervous system) and repeated bleeding in 2. Etiology of the ulcer disease was determined in 15 of the children, but the cause was unknown in 12. Our series is concerned only with duodenal ulcers which, admittedly, comprise the greatest percentage of peptic ulcers.