The ameloblastic fibroma, ameloblastic fibrodentinoma, and ameloblastic fibro-odontoma are mixed odontogenic tumors that are considered to arise from both epithelial and mesenchymal elements of the tooth germ. This article presents the clinical and histopathologic characteristics of 23 new cases. The patients' ages ranged from 3 to 19 years (median 9). Most tumors were asymptomatic and were associated with an unerupted tooth or teeth. All patients were treated with simple enucleation of the tumor. We found that histologically these lesions comprise a spectrum. Some were probably benign odontogenic tumors (neoplasms) and others were odontomas undergoing maturation (hamartomas); however, in any given case we were, on histologic grounds, unable to differentiate the two. The majority, if not all, of our cases were nonaggressive with little or no tendency to recur, whereas some reported cases have exhibited local aggressiveness and recurrence, suggestive of neoplasia. In our opinion, it is clinically important to distinguish the mixed odontogenic tumors from ameloblastoma since the mixed tumors, found mostly in children, are relatively benign when compared to ameloblastoma, which is found in all age groups (usually adults). The usually innocuous behavior of these lesions does not justify aggressive treatment initially, and simple enucleation should be appropriate in most cases.