Acute, parainfectious, disseminated encephalo-myelitis (ADEM) is usually treated with corticosteroids. Intravenous immunoglobulins have not been applied to patients with ADEM. This article describes a 22-year old woman who developed progressive paraparesis, ascending sensory dysfunction, and urinary incontinence one week after tonsillitis. Guillain-Barré syndrome was diagnosed initially, and intravenous immunoglobulins (0.4 g/kg daily) were begun. Symptoms deteriorated after the first and second applications, but after the third application the patient's sensory level declined. After the fourth application, the deterioration of symptoms stopped and cerebrospinal fluid (CSF) abnormalities improved. Because of diffuse spinal cord swelling, intramedullary edema, and hyperintense white and grey matter lesions in the basal ganglia and the corpus callosum on MRI scans, the diagnosis was corrected to ADEM. It is concluded that initial administration of intravenous immunoglobulins might be of therapeutic value in patients with ADEM.