The present study describes the effects of losartan and the angiotensin-converting enzyme inhibitor enalapril on blood pressure, echocardiographically calculated left ventricular mass, renal function evaluated by glomerular filtration rate and quality of life. The renin-angiotensin-aldosterone system is of importance for cardiovascular growth. There is substantial experimental documentation in animals that the angiotensin II antagonist, losartan, decreases the cardiac hypertrophy response caused by elevated arterial pressure as well as intravascular volume overload. However, data in humans is scarce. This is a 3-year, randomised, doubleblind study with parallel group design in 50 patients with essential hypertension. The results show that both drugs reduced blood pressure equally effectively, and also left ventricular mass (P Ͻ 0.001). After 3 years of treatment glomerular filtration rate significantly increased with losartan (P Ͻ 0.005). Serum uric acid fell modestly although significantly, dose-dependent in los-