DUPLICATIONS of the duodenum are commonly thought to represent a surgical problem occurring in infancy. A careful review of the literature reveals, however, that 33% of patients reported were 20 years of age or older.1-14 As these lesions usually cause obstruction and require surgical management, it is important for surgeons who are dealing primarily with adult patients to be aware of duodenal duplications and be familiar with their operative management should such a rare case be encountered. This report describes a patient who presented with a duodenal ulcer and obstruction from a duodenal duplication at 51 years of age. Report of Case A 51-year-old white man was admitted to the Ann Arbor Veterans Administration Hospital on July 26, 1965, with a three-week history of nausea, vomiting, and a 15.9-kg (35 lb) weight loss. He had been free of gastrointestinal symptoms except for a brief episode of nausea, vomiting, and