Although vascular dementia was described over a century ago, it remains a difficult and challenging diagnosis. Several sets of clinical criteria have been published in an effort to establish the presence or absence of vascular dementia in a standardized fashion. Clinical studies have demonstrated that they identify different groups of patients and are thus not interchangeable. Retrospective clinicopathological correlations have shown that most are insufficiently sensitive, although they are generally relatively specific. They accurately exclude pure Alzheimer's disease but may include 9% to 39% of mixed dementia cases (Alzheimer's disease and vascular dementia combined). Further studies are needed to develop better performing criteria that could lead to a broad consensus on the clinical diagnosis of vascular and mixed dementia.