Osteoma of the temporal bone is extremely rare. The authors experienced recently a case of a huge osteoma of temporal bone. A 23 year old Korean soldier was admitted with chief complaints of diffuse swelling of the temporal region on the left side and dull headache which had gradually developed for about 15 years prior to the entry on Nov.-15-1972. On the initial physical examination, the left temporal area revealed a diffuse swelling mass and slightly occlusion of external auditory canal by protrusion of the tumor mass. X-ray examination demonstrated the evidence of the questional mass density on the left mastoid region with questionable calcareous densities and bony mass in it which is suspected as osteoma. The histopathological finding was firmly confirmed as the osteoma of the temporal bone. On Nov. -28-1972, the temporal bone mass was removed partially.