The various antihypertensive regimens have varying effects on glucose metabolism and the development of diabetes mellitus. Recent large hypertension trials have shown great differences in the development of new-onset diabetes among antihypertensive drug therapies. The incidence of diabetes is unchanged or increased by thiazide diuretics and b-adrenergic blockers, and unchanged or decreased by angiotensin-converting enzyme inhibitors, calcium channel blockers, and angiotensin-receptor blockers. The differences in new-onset diabetes mellitus have not influenced the outcome of cardiovascular mortality and morbidity in all of the large clinical trials, but drug-induced diabetes among hypertensive patients is known to carry the same cardiovascular risk as that seen in patients with previously known diabetes; however, it might take years for the increased risk to become apparent.