A 46-year-old man presented with right loin tenderness following a road traffic accident. Computed tomography and magnetic resonance imaging showed a well-defined, smooth, enhancing oval lesion in the wall of the first part of the duodenum. The lesion was seen separately from the normal pancreas. It showed attenuation, intensity and enhancement similar to that of normal pancreas. Based on the imaging appearance, a diagnosis of ectopic pancreas was made. The patient underwent oesophagogastroduodenoscopy, endoscopic ultrasonography and fine-needle aspiration cytology of the lesion, which confirmed ectopic pancreatic tissue. Since the patient was asymptomatic, surgical resection was deferred. The embryologic origin, various locations, imaging appearance and clinical significance of ectopic pancreas are discussed.