Group-A-streptococcus-(GAS)-induced toxic shock syndrome (TSS) is uncommon, but carries a high risk of maternal mortality during pregnancy. The onset of gravidic GAS-TSS has been reported mostly during the puerperium. A 16-year-old woman, who was at 37 weeks of gestation, and without obstetrical care during the last 30 weeks, was referred to our hospital. She complained of fever for one day with headache and abdominal pain after the fever developed. On admission, her consciousness was drowsy, intrauterine fetal death was recognized, and she rapidly developed shock status with coma and hypotension, hemolysis, disseminated intravascular coagulation (DIC), and multi-organ failure. Although we had not obtained the results of a bacterial culture, we suspected sepsis with DIC with homolysis and multi-organ failure resulting from an infection. The patient was treated with antibiotics and intubation because of respiratory insufficiency. Twelve hours after admission to the intensive care unit in our hospital, she died. Cultures from blood, subcutaneous tissue, vaginal discharge, and pharynx all revealed GAS bacteria, and therefore she was diagnosed as having GAS-TSS. GAS-TSS in pregnancy is rare. However, once the infection occurs in a pregnant woman, it rapidly develops into sepsis with multi-organ failure. Therefore, early recognition and intensive treatment for GAS during pregnancy is recommended in women with high fever, muscular pain, hemolysis and DIC during pregnancy.