This 19-year-old female patient visited this hospital on May 9, 1967 with a walnut-sized hard, non-tender mass and diplopia in the frontal region extending to the inner side of the left upper lid for the past two years. X-ray showed a bony shadow which occupied the left frontal sinus completely ; the other paranasal sinuses showed no change. Since this case of osteoma originating at the paranasal sinuses is comparatively rare which cured by surgical extraction, we report this case.