An estimated 2 % to 5 % of all persons with multiple sclerosis (MS) have onset of symptoms before 16 years of age Krupp and Hertz (Neurology 68(Suppl 2), 2007). As in adults, the diagnosis of pediatric MS is a clinical one, requiring recurrent episodes of CNS demyelination with supportive paraclinical data (MRI findings, CSF characteristics) in the absence of another plausible diagnosis. The differential diagnosis is broad and, the more atypical the case and the younger the child, the more consideration is necessary before making a diagnosis of MS. MS must be differentiated from acute disseminated encephalomyelitis (ADEM) or neuromyelitis optica (NMO). After initial presentation with a CNS demyelinating event or clinically isolated syndrome (CIS), children can meet the diagnostic criteria for MS if serial changes are noted on MRI and other disorders are excluded. Accurate diagnosis of pediatric MS is critical because of the implications of the diagnosis, including the need for long-term disease modifying therapy.