The occurrence of duodenal ulcer in infants and children has been reported frequently,1-5but there is little information available concerning the later histories of patients in whom a duodenal ulcer was diagnosed in early life. An effort has been made in this study to determine how many patients with such a diagnosis continued to exhibit signs and symptoms over periods up to 27 years after the time of first diagnosis. Material Duodenal ulcer was diagnosed in the cases of 109 infants and children observed at the Mayo Clinic in the years 1930 to 1958 inclusive. One infant, aged 24 hours, presented with severe gastrointestinal hemorrhage, died, and was found at necropsy to have a duodenal ulcer; two patients died from causes unrelated to ulcer; and 14 more were eliminated from the study because of insufficient follow-up data. The information offered here concerns the remaining 92 patients. In 90 cases,