Acute disseminated encephalomyelitis (ADEM) is a demyelinating disease of probable autoimmune etiology. The MR images of patients with clinically suspected ADEM were retrospectively reviewed. The clinical symptoms occurred 5 days to 1 month after viral upper respiratory infection (4) and Coxsakie viral infection(1). The symptoms had begun with fever(3), headache(3), sore throat(1), and drowsy mental state (1), which progressed with monophasic course to altered mental change(2), extremity weakness(2), seizure(1) and/or cerebellar symptom(1). MRI findings of ADEM showed patchy(4), nonhemorrhagic(5), asymmetric(5) high signal intensity lesions on T2-weighted images. The number of the lesions was mostly multiple(4). The lesions mainly involved the brain stem(3) and subcortical white matter (3). Follow-up MR images of 13 days to 20 days after high dose steroid therapy showed marked improvement in two of three, which well correlated with clinical manifestations. MR findin of multiple, patchy, nonhemorrhagic and asymmetric lesions in subcortical white matter and brain stem on T2-weighted images seem to be characteristic features of ADEM, but nonspecific. Therefore, clinical correlation is required in evaluating ADEM