A 78-year-old woman was admitted for severe heat stroke with brain damage. She was unconscious on arrival at the emergency room. Her armpit temperature was 42.0 degrees C and blood pressure was 76/25 mmHg. She was rapidly cooled and given intensive treatment. On magnetic resonance imaging, T1- and T2-weighted images showed no significant signals, but diffusion-weighted images demonstrated localized symmetrical injuries of the cerebellum and thalami. She gradually became conscious, but severe cerebellar ataxia persisted.