Renal parenchymal disease is a common but often unrecognized cause of hypertension. Chronic renal disease and systemic hypertension may coexist in two distinct settings. First, essential hypertension is an important cause of chronic renal disease. Second, renal parenchymal disease is a well-established cause of secondary hypertension. Renal parenchymal disease is the most common cause of secondary hypertension, accounting for 2.5% to 5.0% of all cases of systemic hypertension.1 Secondary hypertension may also accelerate the decline in renal function if inadequately controlled.1-9 Therefore, hypertension is both a cause and a consequence of renal disease, and it may be difficult to distinguish them clinically.