The central nervous system inflammatory demyelinating disorders of childhood include both monophasic self-limited and chronic lifelong conditions, which can be indistinguishable at the time of initial presentation. In 2007, an International committee proposed diagnostic criteria for CNS demyelination in children. In this study, we review the recent consensus definitions for acquired inflammatory demyelinating diseases and analyze the clinical course and predictor of increasing risk of the second demyelinating event in Korean children. A retrospective review was performed about the medical records of the pediatric patients who were diagnosed with acquired inflammatory demyelinating diseases at Samsung Medical Center, Seoul, Korea. We identified 40 patients (23 female, 17 male), including CIS 80%, ADEM 17.5% and NMO 2.5%. Average age of onset was 8.7 years. Nineteen patients (19/40, 47.5%) experienced the second event. Average interval between first and second event was 21 (0.8-69) months. Finally, 27.5% patients diagnosed with MS, during a mean follow up of 6.2 (2.4-12.9) years. The age, sex, initial clinical presentation, presence of abnormality in the initial brain MRI and CSF study findings did not influence upon the recurrence in CIS group. With the diagnosis of initial inflammatory demyelinating disorder, a thorough investigation of the other CNS areas to find out concomitant lesions and the serial follow up over at least 2 years are recommended for the early diagnosis and immediate treatment.