Hearing impairment is often due to ossicular fixation or destruction following middle ear infection, and many methods and materials have been used to improve hearing loss, Therefore, we have researched the effects of incus interposition technique in tympanoplasty and mastoidectomy patients for about 13 months from Jan. 1980 to Jan. 1981 following are the date we have obtained interposition. 1) The total number of patients who were operated for hearing improvement was 94 cases. Out of these, incus interposition patients totaled 11 cases, of which 7 were mean and 4 were women. 2) Air bone gap(A-B gap) averaged 44 dB preoperatively and 21 dB postoperatively in the two stage operation, and 46 dB preoperatively and 18 dB postoperatively in the one stage operation. 3) For the materials used in the incus interposition technique, banked ossicle was used in 4 cases and patient's ossicle used in 6 cases, malleus was used for repositioning in 1 case. Temporalis fascia was used routinely for drum grafts.