Annular pancreas is a rare congenital anomaly characterized by the presence of ectopic pancreatic tissue surrounding the duodenum. This malformation is usually asymptomatic in adults, but can manifests as pancreatitis, duodenal stenosis, or duodenal or gastric ulceration. We report the case of a young patient of 18 years old hospitalized for epigastric pain and vomiting, in whom radiological investigations showed an annular pancreas. At operation, a complete obstruction of the duodenum between its first and second parts was found, caused by an annular pancreas. No other congenital anomaly of the intra abdominal organs was noted. A gastroenterostomy was performed. Both the rarity of this congenital abnormality and its successful correction by surgical means have prompted us to make the following presentation.