Heat stroke is a potentially fatal disorder that's caused by an extreme elevation in body temperature. We report here an unusual case of multiple organ failure that was caused by classical, nonexertional heat stroke due to taking a warm bath at home. A 68 year old diabetic man was hospitalized for loss of consciousness. He was presumed to have been in a warm bath for 3 hrs and his body temperature was 41 °C. Despite cooling and supportive care, he developed acute renal failure, disseminated intravascular coagulation (DIC) and fulminant liver failure. Continuous venovenous hemofiltration was started on day 3 because of the progressive oligouria and severe metabolic acidosis. On day 15, septic ascites was developed and Acinetobacter baumanii and Enterococcus faecium were isolated on the blood cultures. In spite of the best supportive care, the hepatic failure and DIC combined with septic peritonitis progressed; the patient succumbed on day 25.