Were port a caseof an 82-year-old man who presented with vomiting. Computed tomography(CT)revealed a jejunum tumor and small bowel obstruction. Enteroscopy revealed a protruded lesion and biopsy indicated adenocarcinoma. PET-CT revealed nothing without jejunal tumor. Therefore, with a preoperative diagnosis of primary small bowel cancer, we performed operation. Surgery indicated peritoneal disseminations and a jejunal tumor 40 cm distal from the ligament of Treitz, and we performed small bowel partial resection. Pathological examination revealed adenocarcinoma originating from a Heinrich type I ectopic pancreas in the jejunum. Ectopic pancreatic cancer in the jejunum is rare, and we review case reports in the literature.