Hypertension and type 2 diabetes mellitus (DM) are major cardiovascular risk factors, and often cluster in the same individual in the context of the metabolic syndrome. Management of hypertension in the diabetic patient is extremely important, and agents from all major antihypertensive classes are effective towards this goal. Conventional beta-blockers are associated with detrimental effects on insulin sensitivity, glycaemic control, and the incidence of type 2 DM and thus are less often used in hypertensive patients with DM. In contrast, the newer vasodilating beta-blockers appear to be free of adverse effects on the above metabolic parameters, and could be a valuable tool for hypertension treatment in patients with DM or the metabolic syndrome. This review summarizes the evidence on the effects of antihypertensive treatment with both traditional and vasodilating beta-blockers on parameters related to carbohydrate metabolism, and discuss the pathophysiological mechanisms that may be responsible.