We studied the clinical picture of 160 children with acute tonsillitis that were cultured for streptococcus B hemolytic 51 (319%) were, positive for group A, 20 (12.5%) for group B, C and G, and 89 (55.6%) were negative. The following clinical features were significantly associated with isolation of group A streptococcus: previous episodes of acute tonsillitis severe sore throat, astenia, tonsillar exudate, petechial on the palate, and cervical adenitis. Emphasis is made about the importance of the bacteriological diagnosis of acute tonsillitis.