Acute encephalitis with refractory, repetitive partial seizures (AERRPS) is a peculiar form of encephalitis mainly affecting children. Although not usually lethal, we report a case of sudden unexpected death in epilepsy (SUDEP) 3 years after the onset of AERRPS. A 6-year-old boy was admitted to our hospital because of fever and extremely refractory partial and secondary generalized seizures with delirium and psychiatric change. The seizures were highly resistant to anticonvulsants and suppressed only by large dose intravenous administration of midazolam. Seven months after the onset, the seizures were ameliorated by treatment with potassium bromide and clorazepate. After the acute phase, the patient developed complex partial seizures that tended to present with cyanosis. At the age of 10, he was found lying prone in respiratory arrest with facial pallor. Although he regained cardiac function after being taken to our emergency room, the patient died 12 days later. Six SUDEP cases after the onset of AERRPS, including this one, have been reported to date. Since epilepsy following AERRPS is one of the risk factors of SUDEP, clinicians should consider SUDEP to be a rare but high risk syndrome in AERRPS-afflicted children.