A new case of right coronary artery abnormally issued from the pulmonary trunk is reported. The patient was an asymptomatic young man in whom a continuous cardiac murmur was discovered by chance and an angiographic examination disclosed the coronary abnormality. A review of the literature yielded 37 cases of this anomalous origin which was either isolated, as in the case reported here, or associated with another congenital or acquired cardiopathy. The diagnosis may be suspected on the presence of a continuous murmur in an usually asymptomatic subject and is confirmed by angiography. The abnormality is generally well tolerated owing to an inter-coronary collateral circulation resulting in retrograde perfusion of the right coronary artery from the left coronary artery. This good tolerance explains why an isolated abnormality of that type is often discovered belatedly, in contrast with the anomalous origin of the left coronary artery from the pulmonary trunk, which is usually revealed at birth by clinical signs of acute coronary insufficiency. However, the likelihood of either cardiac failure due to the left-to-right shunt in elderly people or, chiefly, acute myocardial ischaemia by coronary steal with a risk of sudden death in young people makes it imperative in such cases to perform reimplantation surgery.