Atherosclerosis and cardiovascular disease (CVD) are the main causes of death in the Western world, for both men and women. The onset and development of diseases of the cardiovascular and cerebrovascular system are strongly dependent on multiple risk factors that promote pathologic conditions like atherosclerosis, hypertension and thrombosis. Besides genetic factors also environmental influences such as diet composition are known to be closely related to CVD. In this context obesity has been postulated as an independent cardiovascular risk factor. Data from the Framingham Heart Study have consistently shown that increasing degrees of obesity are accompanied by greater rates of CVD. At present, obesity affects 10-35% of the European and US population and increases steadily. As obesity is a serious health problem which promotes metabolic abnormalities (insulin resistance, hyperinsulinemia and dyslipidemia) and dramatically increases the risk for CVD, this review will focus on the epidemiologic and genetic background of obesity. Furthermore, the molecular mechanisms involved in obesity development and their contribution to CVD will be discussed.