Abstract 1. 1. Ameloblastomas are rare epithelial tumors which may arise from the cells of the dental lamina, epithelium of dental cysts, or possibly from the basal epithelium of the oral mucosa. Although rather elaborate classifications have been devised, most cases show one of two major patterns: (1) a follicular type in which the tumor elements form masses resembling enamel organs and (2) a plexiform type consisting of large, branching masses of stellate epithelial cells. 2. 2. Our review of the literature shows that 1,036 cases of ameloblastoma have been reported. About 1 per cent of cysts and tumors of the jaws may be expected to be ameloblastomas. The average age at time of discovery was 32.7 years. Eighty-one per cent of these tumors are found in the mandible, with the molar-ramus area the most frequent site of involvement. There are no apparent sex or racial differences in the incidence of this tumor. 3. 3. Thirty-three cases of “malignant” ameloblastoma have been reviewed. These papers have been studied critically and it would appear to us that most of them are not well documented as to pathologic findings, or that doubtful criteria of malignancy were used. Ameloblastomas should be regarded as locally invasive, persistent tumors. The high rate of postoperative recurrence is due to the mode of growth of this tumor and surgical mismanagement, rather than to any inherent “malignant” properties. Metastasis of this tumor is so exceedingly rare that it is unjustifiable to consider ameloblastomas as more than locally invasive neoplasms. The pathologist must be careful to differentiate invasive epidermoid carcinomas and salivary gland carcinomas from ameloblastomas. Undoubtedly, some of the reported “malignant” ameloblastomas are actually examples of these tumors. 4. 4. The tumor variously known as soft odontoma or mixed odontogenic tumor also should be separated from the ameloblastomas. This lesion occurs most often in young patients and has a good prognosis with conservative therapy.