Ameloblastic fibro-odontoma (AFO) is a quite rare, mixed odontogenic tumour generally seen in the early stages of life. Frequent signs of the tumour are asymptomatic swelling, delayed tooth eruption and mixed radiological appearance within well-defined borders. Management of the lesion includes enucleation of the tumour and long-term follow-up in order to avoid recurrence. A 9-year-old girl was referred to our clinic with swelling in her right cheek. After clinical and radiographic examination, a large lobular radiopaque mass with a radiolucent border covering the complete right maxillary sinus was observed. Under general anaesthesia, the lobules of the lesion were enucleated and the permanent right lateral incisor and canine teeth were left for eruption. Histological assessment revealed a final diagnosis of ameloblastic fibro-odontoma. Post-operative healing was uneventful and the remaining teeth erupted normally. No recurrence was observed during the 3 years' follow-up period. © 2008 The British Institute of Radiology.