Chronic tonsillitis has long been one of the most common disease in the otolaryngologic field. In the microbiologic study of chronic tonsillitis, there has been many reported by many investigators. But the distribution of bacterial flora of tonsils was variable according to the each investigators. To investigate the microbial flora of tonsil, the surface & core tissue of 71 children under went tonsillectomy for either recurrent infection or airway obstruction were cultured aerobically, the number of bacterial colonies were quantitated, and the sensitivity test to antibiotics were done from December 1988 to April 1989 at the Dept. of E.N.T., Yeungnam University Hospital. The results obtained were as follows ; 1) In the infection group, α-hemolytic Streptococcus <33 strains(40.2%), 29 strains(37.1%)> was most frequently isolated, and in decreasing order Staphylococcus aureus <10 strains(12.2%), 12 strains(15.4%)>, Group A β-hemolytic Streptococcus <8 strains(9.8%), 8 strains(10.2%)>, Streptococcus pneumoniae <3 strains(3.7%), 2 strains(2.6%)> as pathogenic bacteria, and Streptococcus epidermidis <14 strains(17.1%), 13 strains(16.7%)> was most frequently isolated as non-pathogenic bacteria on the surface and core tissue of tonsillar culture. 2) In the obstruction group, α-hemolytic Streptococcus <22 strains(32.3%), 20 strains(29.8%)> was most frequently isolated, and in decreasing order Group A β-hemolytic Streptococcus <17 strains(25.0%), 17 strains(25.4%)> Staphylococcus aureus <8 strains(11.8%), 7 strains(10.4%)>, Streptococcus pneumoniae <3 strains(4.4%), 4 strains(6.0%)> as pathogenic bacteria, and Staphylococcus epidermidis <9 strains(13.2%), 10 strains(14.9%)> was most frequently isolated as non-phathogenic bacteria on the surface & core tissue of tonsillar culture. 3) The sensitivity test revealed that it susceptible to penicillin, chloramphenicol, ampicillin, cephalosporin in α-hemolytic Streptococcus and Group A β-hemolytic Streptococcus, to methicillin, cephalosporin in Staphylococcus aureus, and to penicillin, methicillin, ampicillin, cephalosporin, gentamycin in Streptococcus pneumoniae. 4) There were no significant difference of microflora of palatine tonsil not only surface & core tissue of tonsillar culture but also in infection group and obstruction group.