Hypertension and kidney function are intimately related, with each having significant influences on the other. Given the major role played by the kidney in maintenance of extracellular fluid volume and peripheral vascular resistance, the kidney is justifiably a target of investigation to determine its potential role in essential hypertension. Conversely, hypertension is associated with progressive renal failure, and hypertension-associated end-stage renal disease is the second leading cause of end-stage renal disease in the United States. It is therefore important that we continue to investigate the hypertension/renal relationship in an effort to better understand the determinants of essential hypertension and to prevent a major cause of end-stage renal disease.