Drinking excessive amounts of alcohol regularly for years is toxic to almost every tissue of the body. On the other hand, epidemiological and clinical evidence shows that light-to-moderate drinking is associated with a reduced risk of coronary heart disease, total and ischemic stroke, and mortality. In the past two decades, metabolic syndrome, the combination of obesity, hypertension, dyslipidemia and hyperglycemia, all are also recognized as major cardiovascular risk factors, has given rise to much clinical and research attention, because of its high prevalence in the world. Therefore, it is of interest to evaluate the overall associations of alcohol consumption with the development of the metabolic syndrome. Recently, the protective, detrimental, or J-shaped associations have been reported between alcohol consumption and the metabolic syndrome. This controversy may be due to the complex mechanistic relation between alcohol consumption and each component of metabolic syndrome, and almost all studies have various limitations and problem points. Prospective studies are therefore needed to confirm the association between alcohol consumption and prevalence of metabolic syndrome, and to assess the influence of alcohol drinking patterns and other possible factors, such as smoking, physical activity, socio-economic status, education, occupation, diet, and exercise. This article reviews the relation of alcohol consumption and components of the metabolic syndrome, and discusses the epidemiological evidence for alcohol's putative vascular protective effects and plausible underlying biological mechanisms.