Retrospective studies of treated hypertensive cohorts have strongly implicated beta blocker therapy as increasing the risk of developing new-onset diabetes. This has led to the latest British Hypertension Society guidelines advising caution when using beta blockers particularly in combination with thiazide-like diuretics. However the National Institute of Clinical Excellence recommends beta-blocker + thiazide combinations as the treatment of choice in patients who are not at increased risk of developing diabetes. Nebivolol is a newer class of beta blocker. Some studies in diabetic hypertensive patients have suggested that nebivolol does not impair insulin sensitivity. The aim of this study is to compare the effect on insulin sensitivity of nebivolol versus atenolol, both in combination with a thiazide-like diuretic, in a group of non-diabetic hypertensive patients.