Hypertension is a frequent complication of autosomal dominant polycystic kidney disease. More than 80% of all patients suffer from this complication. The underlying mechanisms include inappropriate renin secretion and sodium retention. Converting enzyme blockade lowers systemic blood pressure efficiently and this is paralleled by a decrease in renal vascular resistance. ACE inhibitors in autosomal dominant polycystic kidney disease may not only lower systemic blood pressure but also retard the progression of renal failure In this disease.