In this paper we intend to confine ourselves to the strictly surgical aspects of anomalies of the pulmonary veins in a series of 25 patients who were operated on in this clinic. Anomalies of the pulmonary veins are very often associated with communications between the systemic and the pulmonary circulation, such as atrial septal defect, patent ductus arteriosus, or ventricular septal defect. An atrial septal defect existed in 23 of these 25 cases, and a ventricular septal defect in one; only one patient showed an intact atrial septum (partial anomaly of the pulmonary veins). In none of these cases was a patent ductus arteriosus found. In two, the anomaly of the pulmonary veins was associated with coarctation of the aorta. The various lesions are classified in Table I.