Three types of group A streptococcal infections are particularly feared: necrotizing fasciitis, myositis, and streptococcal toxic shock syndrome (TSS). We present 3 cases of necrotizing fasciitis due to Streptococcus pyogenes, one in an immunocompromised patient who had received kidney transplant and 2 healthy patients. Mean age of patients was 52 years (range, 42-67 years), and all 3 were male. One spontaneous case in absence of any obvious portal of entry is reported. The clinical course was initially indolent but quickly destructive. All patients required emergency surgical debridement and intravenous antibiotics. In 2 cases, intravenous immunoglobulin therapy was added. Differential diagnoses include septic arthritis, cellulitis, gout, other causes of tenosynovitis, erysipelas, and deep vein thrombosis.Blood and soft-tissue cultures should be obtained to identify the bacteria, and emergency computed tomography or magnetic resonance imaging scan should be performed to confirm the diagnosis and define the extension of the necrosis. Aggressive surgical debridement in the first 24 to 48 hours and antibiotic treatment, including penicillin and clindamycin, are the cornerstones in the management of these infections. Adjuvant intravenous immunoglobulin therapy might be useful in case of TSS. Diagnostic and treatment delays are the main causes of mortality in these infections.