Acute pharyngitis is one of the most common illnesses for which children visit primary care physicians. Most cases of acute pharyngitis in children are caused by viruses and are benign and self-limited. Group A beta-hemolytic streptococcus is the most important of the bacterial causes of acute pharyngitis. Strategies for diagnosis and treatment of acute pharyngitis are directed at distinguishing children with viral pharyngitis, who would not benefit from antimicrobial therapy, from children with group A beta-hemolytic streptococcal pharyngitis, for whom antimicrobial therapy would be beneficial. Making this distinction is crucial in attempting to minimize the unnecessary use of antimicrobial agents in children.