Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease that occurs as a complication (4-8%) of the John Cunningham (JC) virus in oligodendritic cells. Progressive multifocal leukoencephalopathy is characterized by focal neurological deficits that usually show insidious onset and steady progression. Since the demyelinating lesions can affect various areas of the brain, specific deficits differ from patient to patient. Patients with PML tend to have a prolonged course with multifocal neurological deficits, such as ataxia, hemiparesis, aphasia, and visual field defects that may occur with or without a change in mental status. Here, we present the case of an human immunodeficiency virus (HIV)-positive patient who initially presented with severe headache, vomiting, and generalized weakness, leading to the diagnosis of PML.