High resolution computed tomography has a significant impact on surgical management of individuals with chronic otitis media with cholesteatoma. The purpose of this study is to evaluate diagnostic significance of high resolution temporal bone CT scan regarding to the state of facial nerve and lateral semicircular canal in chronic otitis media with cholesteatoma. The results were as follows ; 1) Diagnostic accuracy of preoperative temporal bone CT scan regarding to the state of facial nerve was 56.3%. 2) Most common exposure site of facial nerve in operation field was tympanic portion(83.3%). 3) Diagnostic accuracy of preoperative temporal bone CT scan regarding to the state of lateral semicircular canal was 80.0%. We conclude that high resolution temporal bone CT scan is very effective for detecting the bony erosions associated with cholesteatoma.