In Poland over 40% of patients are hypertensive. Majority of them suffer from essential hypertension. Its pathogenesis despite intensive studies is unclear. Many factors are thought to be involved in the pathogenesis of essential hypertension: sodium intake, obesity with insulin resistance, renin-angiotensin system, sympathetic nervous system as well as genetic factors, low birth weight and endothelial dysfunction. At present, the role of endothelin-1 is emphasized.