The kidney is both a target and a cause of hypertension. Primary renal disease is the most common etiology of secondary hypertension. Mech- anisms of kidney-related hypertension include a diminished capacity to excrete sodium, excessive renin secretion in relation to volume sta- tus, and sympathetic nervous system overactivity. Conversely, hyper- tension is a risk factor for renal injury and ESRD. The increased risk associated with high blood pressure is graded, continuous, and present throughout the distribution of blood pressure above optimal pressure. Renal risk appears to be more closely related to systolic than to diastolic blood pressure,