Clinical features and microbiologic data on all cases of serious (hospitalized) Group A streptococcal infections in children managed at our institution between 1985 and 1988 are presented. All 6 cases were caused by toxin-producing strains. Four of 6 were toxin A-producing strains whereas none of 58 community-acquired (Group A streptococcal) pharyngeal isolates in the same period was a toxin A producer. A review of the literature on the incidence of toxin A-producing strains provides information suggesting a resurgence of such strains in the late 1980s after a relative disappearance of toxin B production in isolates from these patients was also significantly greater than in the isolates acquired from the community in uncomplicated pharyngitis. These findings suggest a role for exotoxin in severe manifestations of Group A streptococcal disease in children.