Ameloblastic fibroma (AF) is an uncommon benign odontogenic mixed tumor. A case of an AF associated with unerupted and missing teeth is presented. A 13-year-old girl was referred for evaluation of a painless swelling of her right mandible. The most remarkable finding was the resorption of the proximal root of the permanent first molar. The lesion was completely enucleated. Follow-up showed satisfactory bony healing, and the resorbed root was completely surrounded by a continuous layer of intact lamina dura. In most cases, the patient presents to the clinician complaining of an unerupted tooth at the posterior area of the mandible. The most remarkable finding in our case, however, was the coexisting root resorption. This finding could indicate a more aggressive form of AF. AF has a very good prognosis. Malignant transformation is extremely rare. Palabras clave: ameloblastic fibroma, ameloblastic fibrosarcoma, delayed eruption, mandible, root resorption