We treated two rare cases of acute rhabdomyolysis induced by heat stroke encountered during mountaineering. The clinical findings were complicated by severe acute renal failure and disseminated intravascular coagulation (DIC), respectively. Though heat-related disorders occur frequently in mountain medicine in summer, severe and fatal rhabdomyolysis due to heat stroke is rare. It was also noteworthy that both patients had received treatment with antipsychotic drugs including phenothiazine. Even in a moderate exercise activity such as mountaineering, the possibility of rhabdomyolysis should be considered for all cases of heat stroke, especially those with a history of antipsychotic neuroleptics.