Tonsil is not only important for it's frequent local infection and the most common operation performed on the human pediatric population but as a foci of various focal infections such as rheumatism, dermatitis, and others, Many extensive studies have been done on this subject over a period of about 100 years but the bacterial flora of tonsils are continuously changed according to environmental and geographic conditions and by frequent chemotherapeutics. For this reasion, it is desired to study the bacterial flora and their susceptibility to various chemotherapeutic agents. Bacteriologic study by pressure tonsil swab culture from 133 patients with chronic tonsillitis was performed and sensitivity to various antibiotics of isolated strains was assessed. The results were as follows; 1) From pressure tonsil swab culture, 74 strains of pathogenic bacterial flora were isolated and identified. Of these, 9.5% was group A-β hemolytic streptococcus and 29.7% was staphylococcus (coagulase positive) and 43.2% was gram negative bacilli. 2) Bacterial susceptibility to chemotherapeutic agents revealed as follow; Group A-β hemolytic streptococcus was very sensitive to only penicillin, and was moderately sensitive to methicillin, cloxacillin and cefalosporin; while it was rather resistant against streptomycin, chloramphenicol and oxytetracycline. On the other hand coagulase positive staphylococcus was very sensitive to doxycyclin, cloxacillin, gentamycin, leucomycin and streptomycin, but showed resistant against penicillin and oxytetracycline. Gram negative bacilli was very sensitive to kanamycin, gentamycin and streptomycin, but showed resistant against chloramphenicol, oxytetracycline and cefalosporin.