Gastrointestinal ganglioneuroma is a rare benign neoplasm, composed of ganglion cells, nerve fibers, and supporting cells. Ganglioneuromas are presented as lsolated polypoid ganglioneuroma, ganglioneuromatous polyposis, and diffuse ganglioneuromas. We have experienced a case of an isolated ganglioneuromatous polyp in the rectum. The patient was a 58-year-old female sho had experienced low abdorninal discomfort and tenesmus for 6 go 7 months. Colonoscopic examination revealed a polypoid tumor in the rectum. Microscopically, the tumor showed cystic glands, expanded lamina propria, and smooth surface epithlium. Many proliferated ganglion cells with nerve fibers were evident in the lamina propria which ws extended to the submucosa.