Ameloblastic fibro-odontoma is a rare benign mixed odontogenic tumor with histologic characteristics of ameloblastic fibroma and complex odontoma. As with ameloblastic fibroma, it may be asymptomatic or found because of painless swelling and delayed eruption of associated tooth. This report presents a case of ameloblastic fibro-odontoma in the posterior mandible of a 14-year-old girl and analyses its clinical features and radiographic features on plain X-ray film and CT images. (Korean J Oral Maxillofac Radiol 2005; 35 : 55-8)