The case is reported of a 2-year-old boy with a rotavirus-induced mild encephalopathy that presented as transient intensified signal on the splenium of the corpus callosum. The boy also experienced persistent diarrhea, vomiting, fever, and sudden disturbance of consciousness. Although cerebrospinal fluid analysis did not manifest pleocytosis, electroencephalography demonstrated global diffuse slow waves and cranial magnetic resonance imaging demonstrated intensified signal on the splenium of the corpus callosum. Methylprednisolone was infused for 3 days. The disturbance of consciousness disappeared within 24 hours without any other complications, and the splenial signal and electroencephalogram returned to normal within 6 days.