A 41-year old patient with anomalous origin of the left coronary artery from the pulmonary artery was reported. The anomalous vessel was demonstrated by an aortography and its orifice by a selective pulmonary arteriography. Because of progression of disability and to prevent possible sudden death, ligation of the anomalous vessel was successfully done. This case was the third one in whom operative treatment was successfully carried out in the older age group. Since operation, his chest pain disappeared but there was no remarkable improvement of heart size or electrocardiograms. It was emphasized that the recognition of the hemodynamic change was important for the surgical treatment of this anomaly. Some comments on the diagnostic problems were made.