Ameloblastoma is the most common epithelial odontogenic tumor. It may show locally invasive behavior resulting in recurrence and malignancy. Therefore, appropriate diagnosis of this tumor is necessary. The aim of this study was to evaluate clinicopathological characteristics of ameloblastomas in an Iranian population. We present a 40-year retrospective study of patients diagnosed from 1971 to 2010 in the Department of Oral and Maxillofacial Pathology, Faculty of Dentistry, Mashhad, Iran. Information gathered from patient records included age, gender, tumor location and histologic type. The frequency of odontogenic tumors among all lesions was 2.08% and ameloblastoma with 88 samples demonstrated the greatest prevalence (41.5%). Regarding gender, 60% of samples occurred in males. The mean age of studied patients was 33.02± 15.74 years with a peak of occurrence in the third decade of life. The most frequent location of tumor was the mandibles (93.2%). Eighty five (96.6%) tumors were recorded as benign and 3 (3.4%) as malignant. Of benign tumors, 62 (72.9%), 20 (23.5%) and 3 (3.6%) cases were of conventional, unicyctic and peripheral types, respectively. In contrast to most previous studies, the most common histologic subtype in the present study was plexiform. Knowledge of the incidence of ameloblastoma and its clinicopathologic features including most common location, gender and age distribution in different ethnogeographic backgrounds is necessary for accurate diagnosis and proper treatment.