The authors present their clinical and surgical experience with 13 cases of anomalous origin of the left coronary artery from the pulmonary artery. The series confirms the existence of 2 different anatomical types of this anomaly depending upon the different development of the intercoronary collateral blood-flow: the "infantile" and the "adult" types. Mitral incompetence is a frequent associated anomaly which may sometimes be the presenting clinical feature, thus masking the underlying disease. The results with different surgical techniques performed in 7 patients are discussed.