Heat stroke can lead multi-organ damage with hemorrhage and necrosis in the lungs, heart, liver, kidneys, brain and Ut. Heat stroke occurs when the elevation of core body temperatures induce a failure of thermoregulatory mechanism. A four-year-old male African Lion(Panthera leo) showed clinical signs such as panting, tachycardia, hyperthermia, unconsciousness and mydriasis under He hish humidity and hot weather. Clinical treatment and pouring cool water was unsuccessful. Grossly, congestion of lungs and pleura was observed. Yellowish discoloration was observed in the renal cortex. Microscopically, the coagulative necrosis in kidney and congestion of lungs and spleen were observed. In our knowledge, this case was closely associated with acute heat stroke.