The participation of vascular disease in elderly dementia has been clarified to a significant degree in the past decade. The term multi-infarct dementia implies that severe mental impairment can result from thrombosis of large and medium arteries or from multifocal emboli of either cardiac or arterial origin. This is markedly different from the concept, which, unfortunately, is still the generally current view in the lay press, in some medical journals, and in advertisements of pharmaceutical companies, that gradual narrowing of cervical and cerebral arteries produces chronic hypoperfusion of the brain and is the basis of mental deterioration. This concept of generalized cerebral arteriosclerosis or arteriosclerotic dementia is no longer acceptable. Most patients with MID can be distinguished from those suffering from other types of dementia by employing a clinical ischemic score supplemented by electrophysiologic studies, CCT, and neuropsychological testing. Furthermore, the association of MID with severe hypertension and thromboembolism makes early diagnosis imperative, because appropriate treatment may arrest progression and even provide some improvement.