We investigated the distribution of different etiologies underlying Parkinsonism in a hospital-based autopsy collection, studied the demographic data and evaluated diagnostic accuracy using histopathological examination as the gold standard. Out of a total of 9359 consecutive autopsy cases collected between 1914 and 2010, we identified 261 individuals who carried a clinical diagnosis of a Parkinsonian syndrome at death. A detailed neuropathological examination revealed idiopathic Parkinson's disease (PD) in 62.2%, progressive supranuclear palsy (PSP) in 4.2%, multiple system atrophy (MSA) in 2.3%, corticobasal degeneration (CBD) in 1.2%, postencephalitic Parkinsonism (PEP) in 2.7%, vascular Parkinsonism (VaP) in 8.8% and Alzheimer-type pathology (ATP) of the substantia nigra in 8%. The diagnostic accuracy of PD in our cohort was lower (71.2%) than those reported in previous studies, although it tended to increase during the last decades up to 85.7%. Of particular interest, we found that PD, while being the most frequent cause of Parkinsonism, was greatly overdiagnosed, with VaP and ATP being the most frequent confounding conditions.