The peritonsillar abscess is still not only most common complication of the acute tonsillitis, but also important cause of deep neck space infection. We studied retrospectively 43 patients who had been diagnosed as peritonsillar abscess and had admitted in our department of the Wonkwang University hospital from January, 1985 to December, 1988. The following results were obtained ; 1) Male to female ratio was 3 to 1 and predominant in male. It was frequently affected in third decade in 18 cases(42.0%) and fourth decade in 7 cases(16.2%). 2) Unilateral involvement of peritonsillar abscess was in 40 cases(93.0%) and bilateral in 3 cases(7%). 3) It was frequently found in summer in 13 cases(30.2%) and spring in 12 cases(28.0%). 4) The duration of symptom from onset to admission was 5.4 days in average and most from 2 days to 7 days. 5) The recurrent history of peritonsillar abscess was found in 3 cases(7.0%). 6) The major symptoms were acute sore throat in 40 cases(93.0%), dysphagia in 40 cases(93.0%), fever in 26 cases(60.5%), fatigability in 24 cases(55.9%), trismus in 21 cases(48.9%) and dysarthria in 20 cases(46.5%). 7) Among noted 24 cases, pathologic organisms were isolated in 16 cases(66.7%), consisting of 13 cases of single infection and 3 cases of mixed infection. Among isolated 20 strains(including mixed infection). α-Hemolytic streptococcus were in 8 strains(40.0%), β-Hemolytic streptococcus 7 cases(35.0%), Neisseria catarrhalis 2 cases(10.0%), Staphylococcus aureus 1 strain(5.0%), γ-Hemolytic streptococcus 1 case(5.0%) and Klebsiella 1 case(5.0%) in order. 8) α-and β-Hemolytic streptococci were sensitive to Penicillin, Ampicillin, Carbenicillin, Chloramphenicol, Erythromycin, Cephalothin and resistant to Kanamycin. Tetracycline, Gentamycin, Amikin, Methicillin. 9) All patients were satisfactorily treated with only medical treatment in 7 cases(16.3%), needle aspiration of pus in 3 cases(7.0%), I & D in 32 cases(74.4%) and immediate tonsillectomy after I & D in 1 case(2.3%).