Wistar rats with surgically removed 5/6 of renal parenchyma were fed either standard (0.35% salt content) or a high-salt (2%) diet. Half of the animals of each group drunk plain water while the other half was provided water enriched with the angiotensin-converting enzyme inhibitor enalapril (ENA) at a dose of 5 mg/kg/day. In rats receiving standard diet, ENA had a significant inhibitory effect on the consequences of ablation: the rats had normal blood pressure, low proteinuria, and high endogenous creatinine clearance compared to water-drinking controls. The high-salt diet significantly enhanced the sequelae of ablation: a high blood pressure and proteinuria, low clearance, which ENA was unable to prevent in these animals. No plausible explanation for the absence of ENA's beneficial effect is available: one can speculate that, under conditions of high-salt intake, the activity of the renin-angiotensin system is suppressed leaving no place for ENA to exert its effect. We also believe that the highly adverse effect of a high-salt diet in chronic renal failure is due to growth factors other than angiotensin II.