The benign cementoblastoma is a benign odontogenic tumor of cemental-forming tissue, which has an unlimited growth potential. The radiographic appearance of the lesion is pathognomonic and consists of a radiopaque mass surrounded by a thin radiolucent line. This mass is inseparable, radiologically, from the tooth root and is attached to it. Microscopic evaluation suggests that the lesion enlarges by peripheral growth, with the center of the neoplasm being more calcified and inactive than the periphery. We have observed two cases of beneign cementoblastoma{mature calcified stage) occured in the left mandibular first molar of 22-year-old man and 14-year-old man.