Between May 1969 and June 1975, 43 patients with d-transposition of the great arteries, ranging in age from 2 months to 13 years (mean 19 months), underwent surgical correction. In the first 3 patients Mustard's original method was followed. Later a modified procedure was performed using a Teflon patch. Forty-two of the 43 patients had previously had 50 various palliative procedures, of which 30 were balloon atrial septostomy only. Five patients died in hospital (up to 5 weeks after operation). Of the 32 patients with simple repair of transposition of the great arteries (including 3 with ligation of a persistent ductus arteriosus), 3 died. One patient died as a result of complete AV block, one as a result of renal damage associated with unrelieved coarctation of the aorta, and one of cerebral infarction and peritonitis which probably were initiated preoperatively. Six patients who had additional surgery for pulmonary stenosis survived, including 3 patients who had closure of ventricur septal defect, including 2 who had debanding of the pulmonary artery, 2 died in a low cardiac output state. One infant operated on for subpulmonary stenosis developed permanent complete AV block and was successfully treated with a pacemaker. All the patients with combined operations had some problems postoperatively. The survivors improved greatly, but 2 patients died suddenly one, and one and a half years after the operation respectively.