Blood pressure regulation is an integrated physiological phenomenon known to be influenced by many biological processes and by a variety of environmental factors. Epidemiological studies nevertheless suggest that up to 30% of the variation in blood pressure could be due to genetic factors. Thus, mutations in genes that control blood pressure may be the underlying cause of essential hypertension. Arterial blood pressure is critically dependent on the sodium balance and the regulation of renal sodium excretion is one of the most important homeostatic functions of the body. The identification of genes encoding proteins that transport Na+ across cells of the kidney tubules and of those regulating the activity of these sodium-transporting proteins will therefore bring further insights into the pathophysiology of salt-sensitive hypertension.