This 12-week, randomized, double-blind, forced-titration study compared the efficacy of 3 angiotensin receptor blockers. Patients received olmesartan medoxomil 20 mg, losartan potassium 50 mg, valsartan 80 mg, or placebo once daily. At week 4, doses were titrated to 40, 100, and 160 mg once daily for olmesartan, losartan, and valsartan, respectively. At week 8, losartan was increased to 50 mg twice daily and valsartan increased to 320 mg once daily (olmesartan remained at 40 mg once daily). The primary end point was mean change from baseline in seated diastolic blood pressure (SeDBP) at week 8. All 3 medications significantly reduced mean SeDBP from baseline compared with placebo at weeks 4, 8, and 12 (P<.001). At week 8, olmesartan reduced mean SeDBP more than losartan (P<.001); more patients in the olmesartan medoxomil group achieved a blood pressure goal of <140/90 mm Hg (P<.001). Olmesartan did not reduce mean SeDBP significantly compared with valsartan, although more patients attained blood pressure goal with olmesartan (P=.031). At week 12, all agents lowered blood pressure equivalently.