Acute pharyngotonsillitis is an inflammatory syndrome of the pharynx caused by both viral and bacterial infections. Most cases are of viral etiology and occur as part of common cold and influenzal syndromes. The most important of the bacterial infections is due to beta-streptococci. It is important to differentiate streptococcal from viral pharyngotonsillitis because of the response of streptococcal infection to antibiotic therapy and the ineffectiveness of antibiotic therapy in viral infections. Streptococcal pharyngotonsillitis may also be complicated by acute rheumatic fever and acute glomerulonephritis. Streptococcal pharyngotonsillitis still constitutes many problems in regard to diagnosis and treatment mainly because there is not sufficient knowledge concerning the pathogenetic events in these infections. In this review article different aspects on microbiological and clinical diagnosis of streptococcal pharyngotonsillitis, streptococcal carriers and antibiotic treatment are presented.