Acute renal failure has remained a common and serious syndrome associated with high morbidity and mortality. The aim of the present work was to study the role of angiotensin V converting enzyme, prostaglandins and nitric oxide in acute renal failure and to investigate the possibility that the renoprotective action of angiotensin converting enzyme inhibitors is mediated through prostaglandins or nitric oxide. The results of this work showed that angiotensin converting enzyme inhibitor (perindopril) reduced the glycerol induced renal failure in rats proving that angiotensin converting enzyme has a role in the pathogenesis of this condition. On the other hand, injection of the prostaglandin synthesis inhibitor (voltaren) caused non significant increase of the glyceral-induced acute renal failure, this means that prostaglandins has no role in the protection against or pathogenesis of acute renal failure. This work showed. also, that injection of the nitric oxide synthesis inhibitor (L-NAME) aggravates the glycerol-induced acute renal failure, this means that nitric oxide has renoprotective effect. This study demonstrates, also, thatinjection of prostaglandin synthesis inhibitor (voltaren) or the nitric oxide synthesis inhibitor (L-NAME) together with the angiotensin converting enzyme inhibitor attenuates or even completely abolished its renoprotective effect, this gives a good evidence that prostaglandins and nitric oxide mediate the renoprotective action of the angiotensin converting enzyme inhibitors.