One hundred twenty patients with dextro-transposition of the great arteries (TGA) underwent intra-arterial baffle repair using thin Dacron fabric from 1971 to 1979. The ages of the patients ranging from 29 days to 17 years (mean age 28 months). Thirty-five patients had undergone 49 preliminary palliative operations. Early postoperative mortality was 4.8% for patients with simple TGA but was higher among patients with associated ventricular septal defect (26%), VSD and left ventricular outflow tract obstruction (28.5%) and intact ventricular septum with left ventricular outflow tract obstruction (12.5%). Early nonfatal postoperative complications included low cardiac output (23.3%), respiratory insufficiency (35.8%), junctional rhythm (34.1%), superior vena caval (SVC) obstruction (9.1%), and chylothorax (7.5%). Late postoperative mortality for all groups was 7.5% (nine patients). Late cardiac dysrhythmias occurred in 33 patients (40.7%). Normal sinus rhythm has been preserved in all patients since direct, high SVC cannulation was instituted. Late postoperative hemodynamic and angiographic evaluation in 61 patients revealed severe to total SVC obstruction in 12 patients (20.2%) and pulmonary venous obstruction in four patients (6.5%). Among the latter, two patients died following reoperation and another patient died without operation. SVC obstruction was clinically important in only three patients, two of whom have undergone successful reoperation. All other late survivors are acyanotic and clinically well. The Mustard operation has dramatically improved the survival rate and quality of life for patients with TGA. However, postoperative caval and pulmonary venous obstruction are problems which require additional technical modifications and stimulate the search for alternative corrective operations.