Juvenile polyposis is a rare condition characterized by the development of multiple polyps in the gastrointestinal tract. There is increased risk of gastrointestinal neoplasia in patients with juvenile polyposis. We report a case of juvenile polyposis in a 17-year-old woman with a review of the literature. The patient had a family history of colorectal neoplasia. Endoscopically, 30∼40 variable sized pedunculated polyps were observed throughout the colon. Histologically, the characteristic features were dilated cystic glands lined by normal colonic epithelial cells and expanded lamina propria containing inflammatory infiltrates. There were foci of adenomatous change within the largest multilobulated polyp in the cecum. (Korean J Gastrointest Endosc 19(Suppl. 2): S59∼S63, 1999)