Sixteen children with multiple sclerosis, 14 with remitting and 2 with progressive course, and their follow up for 4-16 (mean, 9 years) are reported. The disease manifested in eight children at the age of 1.5-9 years, while in the other eight at the age of 12-14 years. The cases were acute, but had a stronger inclination to remission than in adulthood. In addition to the "classical" symptoms known in adult, multiple sclerosis, papilloedema and acute increased intracranial pressure were observed in nine children. Dehydrating treatment was life saving in these cases. Opsoclonus occurred in two patients, and two children had convulsions, one of whom later developed chronic epilepsy. The CSF was pathological in all the cases. Oligoclonal gamma-globulin subfraction was found in three out of the five patients tested. Three patients died. Histological examination was carried out in two of them; it revealed severe perivenous demyelinisation due to inflammation. Cortisone treatment occasionally with azathioprine reduced the duration of exacerbations, but could not prevent renewed ones and caused severe side-effects. Multiple sclerosis is a rare but not exceptional condition in children. The differences between cases in children and adults are age-dependent.