We describe a case of encephalomyelitis mimicking multiple sclerosis associated with chronic graft-versus-host disease (GVHD) occurring after allogeneic bone marrow transplantation (BMT) for myelodysplastic syndrome. Immunosuppressive therapy, consisting of a therapeutic dose of cyclosporine A and a maintenance dose of methylprednisolone, was effective in treating symptoms. Although central nervous system GVHD is very rare and remains controversial, presentation of neurological symptoms after allogeneic BMT warrants consideration of GVHD in the differential diagnosis.