PURPOSE: Acute disseminated encephalomyelitis (ADEM) is an immune mediated demyelinating disease of the central nervous system (CNS) that produces multiple inflammatory lesions, particularly in the white matter. Clinical course and outcomes of ADEM are diverse. We investigated the clinical characteristics and prognosis of ADEM in children. METHODS: We reviewed medical records of 25 patients aged less than 18 years and diagnosed with ADEM in Severance Children's Hospital from January 2001 to March 2011. Clinical features and brain MRI(Magnetic Resonance Imaging) findings were analyzed. RESULTS: The most common preceding symptom was nonspecific febrile illness (50%), followed by upper respiratory infection (29%) and gastrointestinal symptoms (29%). Common neurologic manifestations included altered consciousness (68%), seizure (25%) and gait disturbance (14%). Subcortical white matter was the most commonly involved region (72%). Among 25 patients, 15 patients (60%) fully recovered and the others had complications. Four patients relapsed and they were classified into multiphasic ADEM (2), recurrent ADEM (1) and suspicious multiple sclerosis (1). CONCLUSION: ADEM shows diverse neurologic manifestations. It is usually monophasic, but rarely relapses. Therefore, distinction between ADEM and multiple sclerosis is difficult. Further studies are needed to find out the factors associated with developing multiple sclerosis in patients with CNS demyelinating disease.