The hereditary nature of familial hypertension has been clearly established by a number of clinical studies. About 30% of the blood pressure variance can be attributed to genetic factors. As a consequence, the relative risk for developing coronary artery disease or cardiovascular death is increased in patients with a family history of hypertension and cardiovascular disease. Patients with such familial history should be considered at the same risk as those who have independent epidemiologic risk factors. The development of molecular genetics allows establishment of a link between high blood pressure, intermediate phenotypes, and the genes involved in blood pressure regulation. Gene markers should be available in the near future that will help to identify patients predisposed to hypertension. The genes of the renin-angiotensin-aldosterone system are good examples of candidate genes whose products are known to participate in blood pressure regulation. The possible involvement of these genes in essential hypertension is critically analyzed.