Several trials clearly demonstrate the importance of correcting hypertension and proteinuria in slowing chronic renal insufficiency (CRI) progression. The relationship between hypertension and CRI is at least partly the consequence of impaired renal hemodynamics, mainly mediated by the renin-angiotensin system. Two classes of drugs have so far been shown to have an antiproteinuric and renoprotective effect, in addition to their antihypertensive action: ACE inhibitors and calcium-channel blockers (at least the non-dihydropyridines) which also interfere with the actions of angiotensin II. The same should be true for the newest angiotensin II receptor antagonists. To find conclusive evidence about the superior renoprotective effect of ACE inhibitors (or angiotensin II receptor antagonists) or calcium-channel blockers, we need well-designed, prospective, controlled and randomized long-term trials; the pharmacological rationale for combining the two classes of antihypertensive drugs is supported by the clinical need to reach a target blood pressure (120/80 mmHg) in CRI patients with proteinuria.