The relationship between cerebrovascular impairment and Alzheimer's disease is a controversial debate. An important and topical aspect in clinical research is the attempt to define the role of atherosclerosis and its determinants in the presentation and evolution of dementia. In this article, we discuss the evidence of the interaction between degenerative and vascular mechanisms in the pathogenesis of dementia. Moreover, we present data about the influence of hypertension and dyslipidemia, usually considered among the most important risk factors for atherosclerosis, on the evolution of Alzheimer's disease. The effects of antihypertensive and lipid-lowering drugs on cognitive impairment will be also discussed.