Schwann cell tumor occurring in the intestines is rare . A 68-year-old female came to our hospital because of hematemesis. Barium enema and colonoscopic examination revealed submucosal tumor in the sigmoid colon. Laboratory data showed mild anemia . No other abnormal finding was found in the blood chemistry. Tumor marker levels of carcinoembryonic antigen (CEA), CA19-9, alpha feto protein (AFP) and neuron specific enolase (NSE) were within normal limits. The exploratory laparotomy confirmed a large sigmoid colon tumor. She received sigmoid colectomy. The resected specimen was a submucosal tumor with central depression, measuring 4.7×3.5×3.0cm in size. The cut surface of the tumor was yellowish hue with necrosis. Histological examination showed spindle-shaped tumor cells with palisading comma-shaped nuclei and the nuclear pleomorphism. Immunohistochemical examination revealed that the tumor was positive for S-100 protein staining, and negative for Actin and for H.H.F. staining. These findings showed that this tumor was of Schwann cell origin. We report here the case in detail of a schwannoma in the sigmoid colon.