Duodenal duplication is an extremely rare congenital abnormality that occurs mostly in children. It represents only 2% to 12% of all gastrointestinal tract duplication. Its clinical presentation is highly variable and non-specific making the positive diagnosis very difficult. Imaging modalities can help to detect the lesions making the diagnosis more accurate before surgery. Here, we report a case of duodenal duplication revealed by chronic abdominal pain and treated by surgical resection in a 26-year-old man. Even in adults, it is necessary to evoke the diagnosis of duodenal duplication in patients with unexplained abdominal pain. Surgical resection remains the treatment of choice and endoscopic treatment is reserved for selected patients in whom surgery is difficult.