A Clinical observation was performed on 134 cases of chronic otitis media who had taken middle ear surgery at Dept. of Otolaryngology of Kyung Hee University from Jan. 1980 to Dec. 1980. The obtained results were as follows ; 1) Among total 134 cases, male were 79 cases(59.0%) and female were 55 cases(41.0%) and age distribution showed 47 cases(35.1%) in 3rd decade, 39 cases(29.1%) in 2nd decade and 35 cases(26.1%) in 4th decade. 2) Large perforations were observed in 46 cases(34.3%), small and moderate perforations in 40 cases(29.9%), total perforations in 24 cases(17.9%), attic perforations in 15 cases(11.2%). 3) Types of operation for middle ear surgery were tympanoplasty in 83 cases(61.9%) and radical mastoidectomy in 44 cases(32.8%). 4) In cases of radical mastoidectomy, high incidence was shown in total defect of ear drum, 14 cases(34.8%) and in cases of tympanoplasty only, high incidence was shown in large perforation, 29 cases(34.9%). 5) In hearing loss according to the degree of ear drum perforation, total absence of drum showed 54.0 dB loss, large perforation 49.2 dB, and small and moderate sized perfortion 37.6 dB. 6) Pathologic changes of middle ear & mastoid antrum showed granulation in 42 cases(31.3%) and granulation & cholesteatoma in 29 cases(21.4%) and slight edematous or normal middle ear mucous in 26 cases(19.4%).