Clinical and statistical study for preoperative hearing loss and operative findings in 102 cases of chronic suppurative otitis media without cochlear involvement, who had been taken mastoidectomy at Dept. of Otolaryngology, Seoul National University Hospital during these two years, was performed. The results were as followings ; 1) Hearing loss was increased with the increase of duration of the disease. 2) Hearing loss according to the ear drum perforation was as followings ; a) 32.6±19.47 dB in the cases of small perforation. b) 33.3±15.32 dB in the cases of perforation on the pars flaccida. c) 43.6±17.93 dB in the cases of large perforation. d) 51.0±10.93 dB in the cases of total defect. Consequently, hearing loss showed increasing trend with the size of ear drum perforation. 3) Hearing loss according to the states of ossicles was as followings ; a) 24.0±10.75 dB in the cases of intact ossicles. b) 40.6±13.02 dB in the cases of the destruction of the malleus. c) 50.3±14.08 dB in the cases of the destruction of the malleus and incus. d) 56.6±8.01 dB in the cases of total destruction of the ossicles. Consequently, hearing loss showed increasing trend with the destruction of the ossicles. 4) In the cases, which was accompanied with cholesteatoma, the size of ear drum perforation and the destruction of ossicles were severe. 5) The development of mastoid pneumatization in chronic suppurative otitis media was underdeveloped in 85.3% and well developed in only 14.7%.