There are 16 possible variations of double outlet ventricle with regard to interrelations of the great arteries and to location of the ventricular septal defect. In a series of 62 cases, approximately two thirds of patients had the great arteries in a side by side relation, and most (28 of 41) had the ventricular septal defect in a subaortic position. In double outlet right ventricle with malposition of the great arteries, the ventricular septal defect was either subpulmonary or subaortic. Four of the 13 patients with subpulmonary ventricular septal defect had a supracristal defect with side by side relation of the great arteries (Taussig-Bing anomaly), and 9 patients had malposition of the great arteries with an infracristal ventricular septal defect. In all patients with subpulmonary ventricular septal defect, pulmonary arterial oxygen saturation was greater than systemic arterial saturation regardless of the relation of the great arteries. Forty patients had subaortic ventricular septal defect. In 24 of these patients, including 7 with malposition of the great arteries, systemic arterial oxygen saturation was greater than pulmonary arterial saturation. However, in 9 patients (25 percent) the reverse was true, as seen in complete transposition of the great arteries and in Taussig-Bing anomaly. Thus, pulmonary arterial oxygen saturation greater than systemic arterial saturation is not reliable evidence of a Taussig-Bing anomaly. Of the 25 patients with such saturation, only 4 had the Taussig-Bing anomaly.