A 46-year-old Chinese woman presented with nausea, recurrent vomiting, and abdominal pain. Gastroduodenal endoscopic examination revealed an oval-shaped submucosal tumor at the prepyloric area on the posterior wall of the stomach. A degenerated gastrointestinal stromal tumor was suspected. Distal gastrectomy was performed and a histological diagnosis of heterotopic pancreas (HPs) was confirmed. The patient had an uneventful postoperative course and was discharged 7 d after operation. The patient remains healthy and symptom-free in the follow-up of 6 mo. This is a report of a case of gastric outlet obstruction resulting from pancreatic heterotopia in the gastric antrum in an adult woman.