We compared the extent of documentation of the diagnoses, vascular dementia and stroke, on inpatient (hospital) medical records and death certificates among 23 multi-infarct dementia index cases and 14 multi-infarct controls without cognitive dysfunction who were enrolled in a hospital-based case-control study and were followed longitudinally. Both the inpatient medical records and the death certificates markedly underdiagnosed vascular dementia when compared to the case-control study diagnosis. Furthermore, the diagnosis of stroke was grossly underdiagnosed on the death certificates. In lieu of the lack of medical record and death certificate documentation of vascular dementia, studies that utilize such information may be in considerable error. Clarification of the criteria for the diagnosis of vascular dementia and greater physician and public awareness of vascular dementia are needed.