The renin-angiotensin system (RAS) is one of the most important systems in physiology and in pathology. The (pro)renin receptor [(P)RR] is a new component of the system that has attracted much attention, being potentially a new therapeutic target, because the binding of renin and of prorenin triggers the activation of the mitogen-activated protein kinase p42/p44 followed by up-regulation of the expression of profibrotic genes. and because prorenin bound to (P)RR becomes catalytically active. The introduction of a renin inhibitor in the treatment of hypertension and of organ damages, together with the discovery of (P)RR, has revived the interest for the RAS and for potential new RAS blockers, in order to optimize RAS blockade in tissues.