Experimental studies indicate that angiotensin II (Ang II) through its type 1 receptor (AT1) promotes cardiovascular hypertrophy and fibrosis. Therefore, the aim of this study was to analyze if chronic long-term inhibition of the renin-angiotensin system (RAS) can prevent most of the deleterious effects due to aging in the cardiovascular system of the normal rat. All the information available on this subject provided by several studies performed by our research group during the last years is been described. A control group remained untreated; treatment was initiated two weeks after weaning. A converting enzyme inhibitor: enalapril (10 mg/kg/day) or an AT1 receptor blocker: losartan (30 mg/kg/day) were used to inhibit the RAS. Systolic blood pressure, body weight, water and food intake were recorded along the whole experimental period. Heart, aorta and mesenteric artery weight as well as histological analysis of cardiovascular structure were performed at 6 and 18 months. Twenty animals of each of the three experimental groups were allowed to die spontaneously. Results have demonstrated a significant protective effect on the function and the structure of the cardiovascular system in all the treated animals. Changes observed at 18 months of age in the hearts and aortas were quite significant, but each treatment completely abolished this deterioration. The similarity between the results detected with either enalapril or losartan treatment, clearly indicates that most of the effects are exerted through AT1 receptors. Moreover, life span was significantly prolonged in both groups of treated animals compared with untreated controls.