Endothelin was isolated and identified in 1988 by Yanagisawa et al. The endothelin family consists of 21 amino acid isoforms endothelin-1, endothelin-2 and endothelin-3. Endothelin receptors are present in many internal organs, e.g. heart, adrenals, kidneys, lung tissue, central nervous system. ET-1 is the main isoform which is synthesized in endothelial cells, muscular coat of arterial wall as well as in heart, kidney and central nervous system. Endothelins affect multiple organ systems and are involved in the pathogenesis of many diseases. Moreover, ET-1 raises blood pressure, induces vascular and myocardial hypertrophy. This paper is also concerned with endothelin receptor blockers which mediate relaxation of resistance arteries and, since they show a hypotensive effect, can be useful in many cardiovascular diseases.