A 76-year-old woman, presented with positive fecal occult blood. She underwent a resection of the pancreatic body and tail under a diagnosis of serous cystadenoma of the pancreas on July 21, 1999.The patient had no particular subjective symptoms, but laboratory examination during a follow-up visit revealed occult blood in the feces. Based on the findings of a barium study and colorectal endoscopy, she was diagnosed as having cancer of the vermiform appendix. Resection of the ileocecum and regional lymph node dissection (D2) were performed. The tumor filled the lumen of the appendix and resembled a polypoid Is tumor, protruding into the cecum. The tumor was a well-differentiated adenocarcinoma arising from the mucosa, with a papillary to tubular structure. The pathological stage of the tumor was rated as 0 (well-differentiated adenocarcinoma in a tubulo-villous adenoma). The depth of tumor invasion was m, ly (0), v (0), and no signs of lymph node metastasis were found. Primary cancer of the vermiform appendix is rare, and early detection is very uncommon. We report a case of primary carcinoma of the vermiform appendix that was detected at an early stage and discuss the relevant literature.