This chapter summarizes the data of some biomarkers that are associated with the presence of vascular disease, and potential markers of different brain pathologies relevant to vascular dementia (VaD) and for differential diagnosis. Many prospective population-based studies have reported an association between increased plasma levels of inflammation markers and an increased risk of atherosclerotic vascular diseases and dementia. Accumulation of extracellular neuritic plaques with a core of fibrillar β-amyloid protein (Aβ) is a characteristic feature of Alzheimer's disease (AD). The main pool of plasma Aβ seems to originate from platelets although a proportion of it originates from cerebrospinal fluid (CSF) and brain. The endothelial cells of the brain capillaries are sealed together by continuous tight junctions and there are few channels running through the cells. These restrictive characteristics constitute the basis of the blood-brain barrier (BBB). The presence of BBB damage supports the diagnosis of VaD.