Abstract： Objective To summarize and review the result of surgical repair of congenital heart disease in infants under 6 months of age.Methods Between January 1997 and December 2007,1387 infants under 6 months of age with congenital heart disease were operated on.There were 675 cases with ventricular septal defect with pulmonary hypertension (VSD/PH),138 with complete transposition of the great arteries (TGA),155 with tetralogy of Fallot (TOF),111 with totally abnormal pulmonary venous connection (TAPVC),54 with coarctation of aorta or interrupted aortic arch with ventricular septal defect [CoA(IAA)/VSD],46 with double outlet right ventricle (DORV),25 with pulmonary atresia with ventricular septal defect (PA/VSD),24 with pulmonary atresia with intact interventricular septum (PA/IVS) and so on.The operative procedure was dependent on different diseases.Follow-up has been conducted in patients with some complex congenital heart diseases.Results In the recent 11 years,the number of surgical repair in infants under 6 months of age,including neonates,with congenital heart disease has been increased.In contrast to the early phase when ventricular septal defect was the major disease treated with surgery,infants with complex congenital heart disease account for half of all cases treated with surgery now.In the meantime,the surgical mortality has been decreased year after year.There were 110 deaths in our group and the total mortality was 7.9% (110/1387).With improvement of surgical procedure,the mortality was decreased from 11.5%-14.4% in 1997 -2003 to 8.6%-8.9% in 2004-2005 to 3.3%-3.8% in 2006-2007.Follow-up data were available for 98 patients in TGA (83.8%,98/117),79 in TAPVC (87.8%,79/90),68 in TOF (48.2%,68/141),13 in PA/VSD (65%,13/20) and 19 in PAA/IVS (95%,19/20).The duration of follow-up ranged from 3 to 86 months.There were 16 late deaths,4 in TGA,10 in TAPVC and 2 in PA/VSD patients.The majority were asymptomatic on follow-up.Mild residual obstruction was seen in 4 cases with TAPVC.Pulmonary hypertension was seen in 5 cases with TAPVC.Mild aortal valve regurgitation,pulmonary valve regurgitation and tricuspid valve regurgitation were seen in 23 eases with TGA (23.5%,23/98).Some PA/VSD patients had second operation.Conclusions Most symptomatic neonates and infants younger than 6 months with critical congenital heart defects can undergo corrective operation under acceptable risk.Due to improvements in perioperative,anaesthetic,surgical,and postoperative care,contemporary hospital mortality can be reduced to 3.3%-3.8%.Palliative procedures still play an important role in the staged treatment of severe complex heart defects in neonates and infants younger than 6 months of age.