Transverse myelitis is a rare complication of Epstein-Barr virus (EBV) infection. This article describes a case of a previously healthy patient with a subacute transverse my-elopathy. The cerebrospinal fluid showed lymphocytic pleocytosis and protein elevation. A magnetic resonance imaging scan demonstrated abnormal spinal cord signal intensity over several cervical and thoracic segments, suggesting the diagnosis of transverse myelitis. The patient was treated with high-dose corticosteroids and had a rapid improvement. Serologic studies for other viruses were negative; antibody tests indicated acute EBV infection. It is thought this represents a case of transverse myelitis associated with acute EBV infection. Although a few similar patients have been reported previously, this case is the first where EBV serology suggested the etiology at the time of diagnosis, when EBV antibody titers and polymerase-chain reaction for EBV DNA in the cerebrospinal fluid were performed, and when a magnetic resonance imaging scan was used for diagnosis and follow-up.