27 patients had canal wall down tympanoplasty(CWDT) performed from March of 1984 until February of 1987. Follow up period was 4.6 months on an average(month to 1 1/2 years). Male was 18, female 9, and average age was 23.4 years(7 years to 44 years). There were 3 groups of disease for CWDT. First, 17 cases(63%) had COM with cholesteatoma. Second, 6 cases(22%) complained of persistent otorrhea following radical or modified residual cholesteatoma related to previous intact canal wall tympanoplasty. Intraoperative findings were wall ossicular necrosis in 11 cases, necrosis of the malleus and incus, and lateral semicircular canal exposure in 5 cases respectively. Hearing restoration had been done for 18 cases and 15 cases could he followed up. Of them, 5 cases(33%) had 31.4/10.4 dB in AC/BC in the pure tone average over 8 weeks. Postoperative complications were minimal. In 20 meatoplasty group, Only(30%) had a mild granulation, which had been treated by 10% AgNO₃ & 2% gentian violet local application. In 7 nonmeatoplasty group, 3(43%) has a mild otorrhea, which has been treated by meatoplasty.