ObjectiveTo explore the clinical effect of delayed sternal closure (DSC) after neonatal cardiac operations. MethodsWe retrospectively analyzed the clinical data of 347 neonates who underwent cardiac operations through midterm sternotomy in Shanghai Children's Medical Center between January 2008 and December 2012. There were 273 male and 74 female patients with mean age of 14.8±8.4 days and mean weight at 3.4±0.5 kg. We analyzed the influencing factors of delayed sternal closure and the relationship between delayed sternal closure and mortality. A total of 127 patients had DSC (36.6%). Ninety-two patients were of primary DSC because of hemodynamic instability in the operation room, and 35 were of the secondary DSC because that the sternum was reopened in intensive care unit during the early postoperative period. The diagnosis of complex congenital heart defects had a high risk of DSC. The incidence of DSC for great artery (TGA), corctation of aorta (CoA), interruption of aortic arch (IAA), total anormalous pulmonary vein drainage (TAPVD), Taussig-Bing malformation, hypoplastic left heart syndrome (HLHS) was 43.2%, 83.3%, 62.5%, 15.6%, 71.4%, and 66.7% respectively. The DSC patients had longer duration of CPB time (141.4±51.7 min versus 108.5±51.9 min) and clamping time (79.3±29.2 min versus 65.4±25.5 min). In 113 patients the sternums were closed 1-11 days after the initial operation. Sixteen patients died ultimately including 2 deaths after the closure of sternum with a mortality of 12.6%. Surgical site infection occurred in 5 patients including 2 severe patients with surgical intervention. ConclusionDSC has been an essential part of neonatal heart surgery. It provides an opportunity for the recovery of cardiac function.