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. The receptor binds renin and the inactive proenzyme form of renin, prorenin, and the binding triggers the activation of the mitogen-activated protein kinase p42/p44 followed by up-regulation of the expression of profibrotic genes. In addition, prorenin bound to (P)RR undergoes a conformational change and becomes catalytically active. Many animal studies have tried to demonstrate a role for (P)RR in hypertension and in tissue damage associated with diabetes, but if they showed that increased (P)RR was found in kidney of diabetic mice associated with glomerulosclerosis and in heart of hypertensive rats associated with cardiac fibrosis, no definite link could be established between elevated (P)RR and cardiovascular and renal pathologies because of the absence of animal models with a tissue-specific (P)RR knock-out and a lack of a (P)RR antagonist. On the contrary, the human and the animal mutations are calling our attention to an essential role of (P)RR during early development, in particular in neuronal development.