An osteoma is slowly growing benign tumor of bone, which occasionally produced symptoms of a space-occupying lesion. Osteoma of the paranasal sinuses is the most common benign tumor originated from the paranasal sinuses and the frontal sinus is the most frequent site of osteoma. Osteoma may occur at any age but the most frequent incidence is the third decade and those are histologically classified as compact, cancellous, mixed type. Recently the authors had experienced one case of osteoma of the frontal sinus which was removed by anterior osteoplastic frontal sinus operation.