We review the role of endothelin (ET) A-receptors (R) on the coronary circulation. ET-1 maintains the normal coronary artery tone. ET-1 plasma levels are increased during and after coronary angioplasty and this increase is related to myocardial ischaemia rather than to mechanical artery injury. ET_AR antagonists inhibit coronary artery vasoconstriction induced by ET release after coronary angioplasty in humans. ET promotes neointimal formation and ET_AR antagonism has been shown to inhibit restenosis after angioplasty in the animal model but not in humans. ET_AR blockade increases coronary blood flow, dilates distal coronary arterial segments and decreases coronary vascular resistance. Coronary collaterals are less sensitive than other coronary vessels to ET-1. ET_AR blockade decreases collateral blood flow and, consequently, perfusion of the ischemic myocardium.