An increase in the incidence and severity of bacteremia caused by group A streptococci was noted in 1993 and 1994 in the Hadassah University Medical Center, Jerusalem. During the 6-year period 1987 to 1992, 12 children with group A streptococcal bacteremia were hospitalized, whereas in 1993 and 1994 there were 17 patients, 5 of them with 1 each of the following severe clinical manifestations: meningitis and septic shock; streptococcal toxic shock syndrome; septic shock; pleural empyema; and fatal outcome. Our 29 patients with group A streptococcal bacteremia were younger than those reported in the literature: 10 (35%) were < 3 months of age; 17 (59%) were < 1 year old. Most children were previously healthy and only 3 had an underlying immunodeficiency predisposing to infection (1 case each): leukemia; Di George syndrome; and congenital nephrotic syndrome. Two children were recovering from varicella. The skin was the most common site of primary infection (16 of 29). The average white blood cell (WBC) count was 18 150 cells/mm3 (range, 2200 to 34,200). The cases were not related epidemiologically and were caused by a variety of M-protein types. Polymerase chain reaction amplification of the genes encoding exotoxins A (speA) and C (speC) was done on 19 isolates and disclosed 2 strains positive for speA and 5 positive for speC. One of the speA-positive isolates was from the single patient with toxic shock syndrome.