Acute disseminated encephalomyelitis associated with the parainfluenza virus has rarely been reported in childhood. A 2.5-year-old girl with acute disseminated encephalomyelitis, who developed bilateral symmetrical lesions in the basal ganglion, thalamus, corpus callosum, cerebral subcortical white matter, and cerebellar medulla on brain magnetic resonance imaging is described. Serological confirmation of parainfluenza virus infection was made 2 weeks following the onset of neurological symptoms. Four months later, the patient had a full recovery. At present, 3 years later, no relapse has been reported and she is leading a normal life. Our case is of interest because of its rarity, the striking brain magnetic resonance imaging, and the good neurological outcome.