Many traditional antihypertensive drugs are linked to various side effects that may cause concern in the hypertensive diabetic patient. The favorable tolerability of angiotensin-converting enzyme (ACE) inhibitors in essential hypertension makes it likely that they will be well tolerated when used in diabetic patients. Data from ongoing studies support the theory that ACE inhibitors lower blood pressure to the same extent in hypertensive diabetics as in patients with essential hypertension. ACE inhibitors do not seem to affect glucose homeostasis adversely; they may even improve glucose tolerance to a small degree. The renal effects of ACE inhibitors in animal experiments suggest a renal-protective effect that can make them especially valuable.