Elevated blood pressure, particularly systolic blood pressure, increases the risk of cardiovascular and renal complications in patients with diabetes. Current national guidelines set the blood pressure goal for those with diabetes at < 130/80 mm Hg, which is lower than the goal for the general population (<140/90 mm Hg). Achieving this goal, however, remains difficult, with blood pressure control rates being lower for patients with diabetes than for those without diabetes. Large clinical trials have demonstrated that in most cases, patients will require 2 or more antihypertensive agents to achieve goal blood pressure. The renin-angiotensin-aldosterone system plays a key role in regulation of blood pressure. The angiotensin AT1 receptor blockers (ARBs), which block the effects of angiotensin II, not only lower blood pressure but also provide target-organ protection. These agents are generally well-tolerated, with a side effect profile similar to placebo. Clinical comparisons of different drugs within the class have shown that olmesartan, the newest ARB, produced greater reductions in blood pressure than other agents and that a greater percentage of patients treated with olmesartan reached target blood pressure. Combining an ARB with a diuretic may allow more patients to reach goal blood pressure.