Norovirus is a common cause of gastroenteritis. We describe the case of a 23-month-old girl with encephalopathy possibly associated with norovirus infection. The viral genome was detected in stool, serum and cerebrospinal fluid (CSF) by reverse transcription polymerase chain reaction. This is the first report of encephalopathy potentially caused by norovirus as indicated by the presence of the virus genome in CSF.