Since the discovery of sulfonamide in the 1930's and penicillin in 1942, antibiotics have been of great benefit in treating infectious diseases. Unfortunately, they do not always result in cure, even when used properly. This bacteriological study was made on 1,421 cases, which revealed that there were the bacterial growth, of the patients who visited the Department of Otolaryngology, Pusan National University Hospital during from March 1979 to June 1984 and following conclusions were obtained. 1) From otorrhea of 856 ears, 919 straines were isolated and among them, staphylococcus was 323 strains(35.1%), proteus 245 strains(26.4%), pseudomonas 226 strains(24.6%) and others 125 strains(13.6%). 2) From nasal discharge of 219 cases, 238 strains were isolated and among them, staphylococcus was 154 strains(64.7%), pneumococcus 19 strains(8.0%), streptococcus 11 strains(4.6%) and others 54 strains(22.7%). 3) In pharyngeal discharge of 346 cases, 410 strains were isolated and among them, staphylococcus was 153 strains(37.3%), streptococcus 116 strains(28.3%), pseudomonas 23 strains(5.6%) and others 118 strains(28.8%). 4) There is increasing tendency of the Gram (-) bacilli, especially proteus & Pseudomonas. 5) There is also increasing tendency of mixed infection(10.3%) in E.N.T. field than past six years. 6) Staphylococcus was sensitive to cephalosporin, amikacin and cefobid, proteus to cefobid, amikacin and carbenicillin, and pseudomonas to cefobid, amikacin and carbenicillin. So I conclude that the resistance of bacteria was increased gradually.