The bacterial flora of the palatine tonsil has been reported several times by many investigators. As the recent report of such study, we are going to present 207 cases of chronic tonsillitis and 43 cases of acute tonsillitis at Dept. of otolaryngology of N.M.C. for one year. Pressure tonsil swab was performed in all cases. 48.3% was positive for pathogenic organisms in chronic tonsillitis, especially beta-hemolytic streptococcus was 41.5% and 41.9% was pathogenic in acute cases. All the chronic tonsillitis patients were checked for ASOT in serum. ASOT over 200 unit was 59.9%. Moreover the age and the sex distribution are discussed and also ASOT according to the different kind of the pathogenic organism.