We analyzed six cases of progressive supranuclear palsy (PSP) from 1 January 1998 to 31 June 2002. All patients underwent a complete range of laboratory tests, head computed tomographic (CT) scan or magnetic resonance imaging (MRI); three were evaluated by formal neuropsychological examination. All were taking L-dopa or dopamine agonists. At the onset of PSP the initial diagnosis was almost always Parkinson's disease. The head CT scan or MRI findings were non-specific, while neuropsychological testing disclosed cognitive impairment, with predominant subcortical-frontal involvement. We emphasize the still obvious current difficulty in diagnosing PSP at an early stage in clinical practice. Therefore it is essential to formulate better clinical diagnostic criteria, to permit correct management of the disease.