Malassez first described ameloblastoma in 1885. Ameloblastoma is an odontogenic tumor and can arise from the epithelial tissue of the odontogenic apparatus. It is most frequently found in the mandible in the third decade, and is considered an uncommon benign tumor. The author experienced a case of ameloblastoma in a 28 year old female with chief complaints of cheek swelling and protrusion of the hard palate for 10 years. We had confirmed ameloblastoma with biopsy, which was developed in the root of the right upper molar teeth extending to lower half of the right maxilla. She received partial maxillectomy. Postoperative follow-up was yet uneventful.