It has long been recognized that arterial hypertension is often a part of a larger constellation of anthropometric and metabolic abnormalities that includes abdominal (or visceral) obesity, a characteristic dyslipidemia (low high-density lipoprotein cholesterol and high triglycerides), glucose intolerance, insulin-resistance and hyperuricemia. These traits occur simultaneously to a greater degree than would be expected by chance alone, supporting the existence of a discrete disorder that, over the years, has been defined by a variety of terms, including plurimetabolic syndrome, the deadly quartet, dysmetabolic syndrome, insulin resistance syndrome, cardiometabolic syndrome and more recently metabolic syndrome (MS). In last years some scientific organizations proposed working definitions for MS. Among these definitions, the one suggested by the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (NCEP-ATPIII) is the simplest and the most commonly applied. The MS is extremely common worldwide. This high prevalence is of considerable concern because accumulating evidences suggest that the MS, even without type 2 diabetes, carries an increased risk for cardiovascular and renal events. Recently it has been demonstrated that the adverse prognostic impact of MS may also be extended to hypertensive patients. Some recent studies reported an increased prevalence of left ventricular hypertrophy, diastolic dysfunction, early carotid atherosclerosis, impaired aortic distensibility, hypertensive retinopathy and microalbuminuria in hypertensive patients with MS when compared to those without it. The increased occurrence of these early signs of subclinical target organ damage, most of which are recognized as significant independent predictors of adverse cardiovascular and renal outcomes, may partially explain the association of the MS with a higher cardiovascular and renal risk.