The metabolic syndrome describes the clustering of dyslipidaemia, glucose intolerance and hypertension with central adiposity. The syndrome is increasing in prevalence worldwide as a consequence of increasing obesity prevalence. It will have global effects on the prevalence of cardiovascular disease. This review summarises current knowledge of the syndrome with special emphasis on the aetiology and pathogenesis and examines the clinical consequences of occlusive vascular disease and non alcoholic steatohepatitis. The roles of nutrition, exercise and pharmacological treatments of the syndrome are discussed.