OBJECTIVE: The authors' goal was to validate the clinical criteria for vascular dementia of the State of California Alzheimer's Disease Diagnostic and Treatment Centers (ADDTC), the National Institute for Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN), DSM-IV, and ICD-10. METHOD: Sensitivity and specificity were assessed by comparing the clinical with the neuropathological diagnosis of 89 autopsied patients with dementia from a geriatric and psychiatric hospital. All cases were reviewed by a clinician and a neuropathologist who were blind to each other's findings. RESULTS: Neuropathologically there were 20 cases of vascular dementia, 23 cases of mixed dementia, and 46 cases of Alzheimer's disease among the autopsied patients. The sensitivity was 0.50 for DSM-IV criteria for vascular dementia, 0.70 for ADDTC criteria for possible vascular dementia, 0.55 for NINDS-AIREN criteria for possible vascular dementia, 0.20 for ICD-10 criteria for vascular dementia, 0.25 for ADDTC criteria for probable vascular dementia, and 0.20 for NINDS-AIREN criteria for probable vascular dementia. Specificity was 0.84, 0.78, 0.84, 0.94, 0.91, and 0.93, respectively. The proportion of cases clinically classified as vascular dementia ranged from 0% to 13% for neuropathologically confirmed cases of Alzheimer's disease and 9% to 39% for neuropathologically confirmed cases of mixed dementia. There was no statistically significant relationship between the neuropathological diagnosis and three of the clinical criteria sets studied (ICD-10 criteria for vascular dementia and ADDTC and NINDS-AIREN criteria for probable vascular dementia). CONCLUSIONS: Clinical criteria for vascular dementia are not interchangeable. The ADDTC criteria for possible vascular dementia are the most sensitive for the detection of vascular dementia; however, the DSM-IV criteria for vascular dementia and the NINDS-AIREN criteria for possible vascular dementia may be more effective in excluding mixed dementia. Given their inability to detect the vast majority of cases of vascular dementia, the ICD-10 criteria for vascular dementia and the ADDTC and NINDS-AIREN criteria for probable vascular dementia should be revised.