Duodenal duplication cyst remains one of the rarest congenital malformations with an incidence of 1 in 5–10,000 live births. Among them, the duplications affecting the duodenum are extremely rare, accounting for only 4–5% of the duplications of the digestive tract. We present a 6-month-old girl with recurrent, nonbilious vomiting. Abdominal sonography showed classical signs of duodenal duplication. Intraoperatively, the distal segment of the duplication showed a fistula-like canal pulling to the pyloric canal. Histologically, uncharacteristically ectopic pancreatic tissue was shown. The operation was successful. Postoperative follow-up was satisfactory. Surgical procedures include endoscopy, laparoscopy or open access. The prognosis after complete removal is excellent.