A substantial level of evidence supports the use of renin system blockade for many patients with hypertension. Two lines of evidence, based on very high-dose angiotensin blocker treatment or combination therapy with angiotensin-converting enzyme inhibitor and angiotensin receptor blocker, suggest that more complete blockade leads to improved clinical outcomes. The recent development of a powerful renin inhibitor that acts at the initial, rate-limiting step in the renin cascade would also favor more complete blockade of the system. For many patients, this is likely to lead to improved treatment.