We herein report the rare case of a 56-year-old man who suffered from heat stroke. Although he was in a coma with convulsions on arrival and developed multiorgan failure, he recovered after two weeks of successful treatments. Hyperintense signals on the right temporoparietooccipital cortex, which disappeared within one week, were demonstrated on diffusion-weighted magnetic resonance images. A diagnosis of transient cortical injury caused by heat stroke was suggested. Although the cerebellum is most susceptible to lesion formation, the mechanisms underlying heat stroke are multifactorial and may result in a variety of brain lesions.