Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disease of the central nervous system that involves multifocal areas of the white matter, rarely the gray matter and spinal cord, mainly affecting children and mostly occurring 1-2weeks after infections or more rarely after vaccinations. Though a specific etiologic agent is not constantly identified, to evaluate carefully patient's clinical history and obtain adequate samples for the search of a potential ADEM causal agent is crucial. In the case of a prompt diagnosis and adequate treatment, most children with ADEM have a favorable outcome with full recovery, but in the case of diagnostic delays or inappropriate treatment some patients might display neurological sequelae and persistent deficits or even show an evolution to multiple sclerosis. The suspicion of ADEM rises on a clinical basis and derives from systemic and neurologic signs combined with magnetic resonance imaging of the central nervous system. Other advanced imaging techniques may help an appropriate differential diagnosis and definition of exact disease extension. Although there is no standardized protocol or management for ADEM, corticosteroids, intravenous immunoglobulin, and plasmapheresis have been successfully used. There is no marker that permits to identify the subset of children with worse prognosis and future studies should try to detect any biological clue for prevision of neurologic damage as well as should optimize treatment strategies using an approach based on the effective risk of negative evolution.