In this study we analyzed the clinical features and surgical treatment of petrous cholesteatoma in 9 patients (9 ears) who underwent surgery at the Jikei University Hospital. Most patients initially experienced hearing loss, then facial nerve palsy or otorrhea. Congenital cholesteatoma was diagnosed in four patients, acquired cholesteatoma in one patient, and postoperative recurrence in three patients. The proportion of cases of congenital cholesteatomas was higher than in previous reports. The area of the cholesteatoma was classified according to Dr. Sanna cases and the supralabyrinthine type in two cases. Hearing preservation surgery was performed in four patients via the middle cranial fossa approach or by partial labyrinthectomy, and the results seemed satisfactory. These results suggested that hearing preservation surgery should be adopted in every case.