Introduction: Ameloblastoma is a benign but locally invasive tumor with a high recurrence rate. The aim of this study was to make an easier diagnosis and treatment planning of ameloblastoma. Materials and Methods: From January 1993 to October 2009, 139 cases from 123 patients, who had been diagnosed with ameloblastoma through radiologic and biopsy in the department of oral and maxillofacial surgery of Kyunpook National University, were selected as the subjects in this study. According to the medical charts, 9 factors (age, gender, location, chief complaints, duration, radiographic findings, size and recurrence) concerned in deciding the treatment method and the relevance between each factor and the treatment methods were examined.(Conservative treatments were marsu-pialization, enucleation, curettage and lateral decortication. Radical treatments included block excision, resection and hemisection) Results: In the patients under the age of 20, 77.14% had conservative treatments, whereas 22.86% underwent radical treatments. In the patients over the age of 20, 44.23% were treated conservatively treatments, and 55.77% underwent radical treatments. For unilocular types, 28.57% had conservative treatments, whereas 71.43% had radical treatments. For the multilocular types, 66.67% underwent conservative treatments, and 33.33% had radical treatments. For the primary cases, 58.68% were treated conservatively and 41.32% had radical treatments. For the recurrent cases, 16.67% and 83.33% underwent conservative and radical treatments, respectively. Conclusion: There was statistical significance in the factors affecting the treatment methods, such as age, radiographic findings and recurrence.