Fifty two consecutive patients with heat stroke were examined for evidence of adult respiratory distress syndrome (ARDS) and disseminated intravascular coagulation (DIC). Twelve patients were found to have ARDS (incidence of 23 percent) of whom nine (75 percent) died. All of these 12 patients had DIC as compared to only one among the 40 patients without ARDS. Review of the evidence in literature linking ARDS and DIC and our own observations in this study lead to the conclusion that the coagulopathy may be an essential mediator of lung damage in heat stroke and is a reliable marker of its occurrence. This suggests the possibility that screening of heat stroke victims for DIC may identify patients at increased risk of developing overt ARDS and allow early institution of measures which may possibly improve survival.