A 30-year-old woman who had until recently been healthy, was transferred to our hospital by ambulance with complaints of dyspnea and pain in both lower limbs. She had 1-week history of sore throat, fever and cough. She had been to a neighboring clinic three days previously, and had been prescribed some medication for bronchitis, but her symptoms had not improved. By the time of admission, she was already in shock and had severe respiratory failure. Laboratory data showed renal dysfunction, disseminated intravascular coagulation, CPK elevation and severe metabolic acidosis. Chest x-ray and CT films revealed consolidation of the entire right lung field. The patient was quickly intubated and we began mechanical ventilation. We immediately initiated broad-spectrum antibiotics, immunogloblin, dopamine hydrochloride and gabexate mesilate, but she died 7 hours later. From cultures of blood and sputum taken from the patient, Streptococcus pyogenes was isolated. On the basis of these clinical and bacteriological findings, we confirmed a diagnosis of pneumonia and toxic shock syndrome caused by Streptococcus pyogenes (STSS). Serologically her M protein was serotyped as M1, and with regard to Streptococcal pyrogenic exotoxin genes were identified as speA and speB. These serological findings were consistent with the most frequent type that causes STSS. In spite of the uncommon cause of community-acquired pneumonia, Streptococcus pyogenes can potentially affect healthy individuals. The pneumonia can be complicated with STSS and so the clinical course may be severe and fulminant. The evidence acquired from this case suggests that in the event of severe pneumonia with shock, we should be aware that this may represent the presence of Streptococcus pyogenes and/or toxic shock syndrome.