PURPOSE: Tympanosclerosis is a common problem causing conductive hearing loss accompanied by chronic otitismedia. The purpose of this study was to evaluate the CT findings of tympanosclerosis, and correlate them with thesurgical findings. MATERIALS AND METHODS: The CT scans of 17 patients with surgically-proven tympanosclerosis andthose of a control group of 34 patients with nontympanosclerotic chronic otitis media were reviewed. According totheir location, they were assigned to one of three groups; tympanic membrane, epitympanum, or ossicles. RESULTS: Tympanosclerosis was found during surgery to be located in the tympanic membrane (n=11), the epitympanum (n=6), oraround the ossicles(n=8). Calcification of the tympanic membrane, ossicular thickening, narrowing of theepitympanum and calcification of the tympanic cavity occurred to a significant extent, and were more often afeature of tympanosclerosis than of nontympanosclerotic chronic otitis media (p <0.05). As an indicater of tympanicmembrane involvement, sensitivity and specificity of calcification of the tympanic membrane were 73% and 83%,respectively. As an indicator of ossicular involvement, the corresponding figures for ossicular thickening were50% and 93% ; as an indicator of involvement of the tympanic cavity (especially the epitympanum) the figures fornarrowing of the epitympanum and calcification of the tympanic cavity were 50% and 50% (respective sensitivities),and 89% and 93%(respective specificities). CONCLUSION: Tympanosclerosis usually appears on CT as ossicularthickening, narrowing of the epitympanum, calcification of the tympanic membrane and/or tympanic cavity. CT isvery helpful in evaluating ossicular involvement and determining the appropriate surgical treatment oftympanosclerosis.