This paper describes four patients with undetected progressive supranuclear palsy who were referred to psychiatric facilities for treatment of late onset symptoms and signs attributed to primary psychopathology. However, subsequent neurological and neuropsychological evaluation established the diagnosis of progressive supranuclear palsy. In two patients, psychiatric symptoms preceded the onset of neurological deficits.It is our experience that because of presenting symptomatology, some patients with progressive supranuclear palsy will be referred for psychiatric consultation. The possibility of progressive supranuclear palsy should be considered in the differential diagnosis of late onset psychiatric syndromes.