Invasive group A streptococcal infection has important diagnostic and therapeutic implications in patients with necrotizing fasciitis. We cared for a man with the full-blown syndrome in whom many features of toxic shock syndrome were present, including profound hypotension and renal failure. The diagnostic similarities of toxic shock syndrome and the toxic shock-like syndrome caused by group A Streptococcus could have led to inappropriate treatment. Successful therapy in our patient included high doses initially of broad-spectrum antibiotics, repeated operative debridement of the lower leg (the affected limb), and ultimately, reconstructive surgery consisting primarily of split-thickness skin grafts. The reemergence of invasive streptococcal infections may relate to changes either in virulence factors of the causative streptococcus or in exotoxins elaborated by this microorganism. A causative relationship between an exotoxin produced by group A Streptococcus and the toxic shock-like syndrome has not yet been established.