Hypertension occurs frequently in autosomal dominant polycystic kidney disease. Increased activity of the renin-angiotensin system contributes to the development and maintenance of hypertension before the development of renal failure. Angiotensin-converting enzyme inhibitors are indicated for treatment of hypertension before the development of renal failure, but in severe renal failure these agents may cause further deterioration in renal function. Treatment of hypertension may not retard the progression of renal failure but is necessary for the prevention of cardiovascular disease.