Essential hypertension, a disease that affects about 60 million Americans, is not a homogeneous clinical entity. The disease is caused by altered regulation of mechanisms that control arterial pressure. Because the manifestations of the abnormally regulated pressure have many factors, the approaches to treatment likewise may be expected to be multifactorial. Hemodynamic, neural and catecholamine, renopressor, renal excretory and volume, hormonal, electrolyte, and depressor mechanisms are discussed. Associated conditions that must be considered include exogenous obesity, hyperuricemia, coronary artery disease, carbohydrate intolerance, and hyperlipidemia. Clearer understanding of the role of each of these factors in essential hypertension should provide a rationale for wise selection of antihypertensive therapy and allow reversal of the very high rates of cardiovascular morbidity and mortality associated with the disease.