Although the introduction of modern neuroimaging techniques and standardized clinical evaluations has improved the identification of cerebrovascular disease, the clinical diagnosis of vascular dementia (VaD) is still problematic. Neuropathologic studies have found the current clinical criteria for VaD had low sensitivity with high specificity, suggesting that cerebrovascular disease of sufficient severity to cause cognitive deficits is frequently associated with other disease processes (eg, Alzheimer's disease). The critical factors about the diagnosis of VaD are centered on two issues: definition of dementia and determination of vascular disease. The current clinical criteria for VaD have different definitions of dementia, which are mainly based on an Alzheimer's disease-like presentation, and severe vascular disease can present with or without history of clinical strokes. Therefore, there is a need for a better definition of VaD. This is extremely important to better understand its risk factors, as well as to create homogenous cohorts suitable for drug trials.