We experienced two cases of rotavirus-related acute encephalopathy.  Each case followed a different clinical course.  The first case is 2-year and 11-month-old girl who had generalized tonic-clonic convulsion at onset. She was severe enough to a require respirator but she recovered without any sequelae.  The second case is 2-year and 2-month-old girl who had a vague symptom of continuous fretfulness. Her EEG showed a slow wave and her brain MRI detected abnormal signals in the cerebellum. Her motor function was recovered but higher brain dysfunction and light cerebellum symptoms remained.   There wene two types of clinical condition on rotavirus-related encephalopathy; Convulsion type and cerebellum lesion type.  Since the latter type is hard to diagnose and to treat, an effective therapeutic strategy should be established.