Vascular dementia has been recognized since the 17th century, but was more clearly defined in the late 19th/early 20th centuries. It results from vascular brain injuries including strokes and small vessel disease. Diagnostic criteria have evolved, with NINDS-AIREN currently most widely used. Pathogenesis involves reduced blood flow and oxidative stress damaging blood vessels and brain tissue. Imaging plays a key role, with MRI best showing lesions and white matter hyperintensities. Higher blood pressure is a risk factor, and controlling vascular risk factors may help prevent cognitive decline.