A 16 year boy was admitted with fever, headache, muscle pain, maculopapular rash and progressive altered sensorium. His serum dengue IgM was positive and was improving on conservative management. The patient developed right hemi paresis after 19 days and his MRI revealed multiple white mater lesions. He was diagnosed as acute disseminated encephalomyelitis (ADEM) following dengue hemorrhagic fever. ADEM is a rare neurological complication of dengue fever. However, the increasing use of magnetic resonance imaging in endemic areas may help to identify ADEM.