The author experienced recently a case of huge osteoma of temporal bone. A 21-year-old young man was admitted on April-3 1969, with the complaints of hearing disurbance and diffuse swelling of the left temporal region, which had gradually developed for about 7 years prior to entry. Clinical examination revealed a diffuse hard swelling of the left temporal region and occlusion of external auditory canal by protruding the tumor mass. Radiological examination demonstrated a huge, round density in left temporal region and sclerotic change on the left mastoid cells. On April 4, 1969, left external auditory canal exostosis removal and tympanoplasty were performed. On April 21 1969, the temporal bone tumor mass removed partially by craniectomy because of wide extension to the base of skull inferiorly and zygomatic arch anteriorly. The histopathological examination of the specimen revealed the osteoma. The patient felt better hearing acuity postoperatively.