The bacteriologic study was made on 162 cases of chronic suppurative otitis media who visited the department of otolgryngology, Seoul Red Cross Hospital during a period of Jan. 1982 through Oct. 1983 and the following results were obtained. 1) In 162 cases in which pathogenic organisms were isolated, single infection was 144 cases(88.9%) and mixed infection was 18 cases(11.1%). 2) The most frequent pathogenic organism was staphylococcus(48.9%) and alkaligenes fecalis(13.9%), proteus(12.2%) were the next. 3) Staphylococcus was highly sensitive to amikacin, cefoperazone, cefoxitin, cephapirin, carbenicillin and highly resistant to penicillin, chloramphenicol. 4) Alkaligenes fecalis was sensitive to amikacin, cefoperazone and highly resistant to ampicillin, penicillin, tetracycline, cephapirin, chloramphenicol, cefoxitin, kanamycin. 5) Proteus was highly sensitive to cefoperazone, amikacin, carbenicillin and resistant to penicillin highly. 6) In the aspect of the sensitivity to antibiotics, amikacin and cefoperazone, carbenicillin, cefoxitin, cephapirin are considered as highly sensitive drugs.