Acute Disseminated Encephalomyelitis is a serious demyelinating disorder of childhood that typically occurs following vaccination or a viral prodrome. Some etiologies remain unrecognized, and multiple mechanisms of immune response may explain the pathophysiology of this syndrome. Based on a report of two adult cases presenting with neurologic deficit and ataxia, we report our experience with this syndrome that may affect adults without evident infectious disorder. Prompt treatment is important to avoid rapid progression.