Temporal bone CT was done in 697 patients from April 1985 to October 1989. The abnormal findings were seen in 453 patients, which were chronic otitis media in 355 patients, fracture in 49 patients and congenital anomaly in 44 patients, etc. The abnormal findings of inner ear were observed on 46 patients. The results were summerized as follows. 1. The incidence of inner ear involvement by chronic otits media was 7.3 % (26/355: labyrinthine fistula in 17 patients, labyrinthitis ossificans in 9 patients). labyrinthine fistula was most commonly located on lateral semicircular canal(15/17, 88.2%). 2. fusion of vestibule with lateral semicircular canal and formation of common cavity was demonstrated incidentally in 5 patients(0.7 % of total number of temporal bone CT), and bilateral in 3 patients. 3. The incidence of inner ear anomaly in congenital ear anomaly was 11.4% (5/44). All cases were bilateral and three patients showed associated middle ear anomaly. 4. The incidence of invo vement of bony labyrinth in temporal bone fracture was 10.2%(5/49). labyrinthine fracture was seen all patients of transverse (3) and mixed fracture(1). In longitudinal fracture, labyrinthine fracture was seen in 2.2%(1/45). 5. Orthers were traumatic labyrinthitis ossificans(1), intrcanalicular acoustic neuroma(3) and facial nerve neuromal(1)