The metabolic syndrome is a cluster of mutually related risk factors that confers an increased risk for both type 2 diabetes mellitus and cardiovascular disease. Although the metabolic syndrome seems to have multiple aetiological factors, microvascular dysfunction is a potential explanation for the above-mentioned cluster of multiple metabolic risk factors such as hypertension, insulin resistance and glucose intolerance. Microvascular dysfunction leads not only to increased peripheral vascular resistance and blood pressure, but may also decrease the insulin-mediated glucose uptake in muscles. The different effect on the microcirculation may explain why some antihypertensive drugs (beta-blockers) lead to an increased incidence of type 2 diabetes, whereas others (angiotensin-converting enzyme (ACE) inhibitors) are associated with a decrease of that risk.