The association of acute myelopathy and encephalopathy is reported in a 13-year-old boy. Signs and symptoms of infectious mononucleosis, presence of heterophile antibodies, anticapsid antibodies and Epstein-Barr virus DNA detected in cerebrospinal fluid, disclosed a primary or reactivated infection by Epstein-Barr virus. Outcome was rapid and benign with complete clinical recovery in 1 month, after pulse therapy with methylprednisolone. Epstein-Barr virus is a known agent related to acute disseminated encephalomyelitis, by immune mediated mechanisms. However, in this case, cortical involvement in magnetic resonance imaging, short time between infectious mononucleosis and central nervous system manifestations, and the presence of viral DNA in cerebrospinal fluid, raised the possibility of a direct action of the virus in central nervous system. Acute myelopathy associated to Epstein-Barr virus encephalitis has been rarely reported in children.