Objective:To determine the incidence of group A hemolytic streptococcus (GABHS) carriers in children who are well, in children seen with presumed and documented viral illnesses with sore throat, and in children after treatment of acute GABHS tonsillopharyngitis with 10 days of oral penicillin V potassium, oral cephalosporins, or macrolides.Methods: Prospective collection of clinical and microbiologic data from October 1996 to June 1997 in a private pediatric practice were obtained from children who were asymptomatic and well, from children with both presumed (and documented) viral sore throats, and from children who had completed a full antibiotic treatment course for acute GABHS throat infections.Results: The incidence of GABHS carriers was 2.5% among well children (n = 227), 4.4% among children with upper respiratory tract infections including sore throat ARTICLE