Tympanoplasty on only hearing ears was performed on 11 patients in Osaka University Hospital and Osaka Rosai Hospital during 1986 1994; this was 0.68% of all cases of middle ear surgery. The patients consisted of 5 with cholesteatoma, 5 with chronic otitis media and 1 with cholesterin granuloma. The mean age was 47.6 years (13-68 years) and the mean follow-up period was 2 years and 7 months (6 months-4 years). Postoperative hearing results was obtained in 9 patients (81.8%) according to the criteria of Otology Japan (1987), and all ears were dry at the final examination. Compared with the preoperative hearing level, postoperative hearing level showed improvement in 3 cases, not in 7 cases (within difference of 5 dB) and deterioration by 10-15 dB in 1 case. Although indications for surgery on only hearing ears are still controversial, we suggest the following: 1) patients with cholesteatoma should be operated on in the ordinary way; 2) patients with chronic otitis media should be operated on only by myringoplasty; 3) all patients must be operated on very carefully by skillful surgeons.