While atrial septal defect is a common associated feature of partial anomalous pulmonary venous return, atrial septum reportedly remains intact in the incidences ranging from 2.2 to 26.0%. We have experienced four cases of isolated partial anomalous pulmonary venous return without other cardiac anomalies including atrial septal defect. Entire right pulmonary veins returned to right atria in two of the cases. Remaining two cases were extremely rare in type. In one of those, right and left upper pulmonary veins returned to superior vena cava and left innominate vein, respectively, and entire left pulmonary veins returned to left innominate vein in the other. Three of the cases underwent complete correction with excellent results.