Abstract： Objective To compare the neonatal outcomes of different gestational age at which elective cesarean sections at term were performed. Methods All the cases of cesarean section registered in Peking Union Medical College Hospital from September 2002 to November 2009 were collected. Women with viable singleton pregnancies delivered before the onset of labor and without recognized indications for cesarean section after 37 weeks at term were included and their general information and outcomes were compared with one-way ANOVA. All the maternal data and neonatal adverse events were compared with Cochran-Armitage test among different gestational weeks, including respiratory complications (respiratory distress syndrome or transient tachypnea of the newborn), infections, admission to the neonatal intensive care unit (NICU), and hospitalization in NICU＞5 d. Results Of 8122 primary cesarean sections and 594 repeat cesarean sections at term, 4565 and 409 cases were performed electively as the primary or repeat cesarean section. Among the 4565 women underwent primary elective cesarean sections, 2194 (48.1%) were before 39 gestational weeks,and 1828 (40.0%) at 39-39+6 weeks. While, among the 409 repeat elective cesareans sections, these figures were 275 (67.2%) and 120 (29.3%), respectively. No fetal or neonatal death occurred during perinatal period. Compared with births at 39-39+6 weeks, births at 37-37+6 weeks or 38-38+6 weeks were associated with increased risk of the neonatal adverse events. For the primary cesarean section cases, the odds ratio (OR) for births at 37-37+6 weeks and 38-38+6 weeks was 1.4 (95% CI: 0.9-2.0) and 1.1 (95% CI: 0.9-1.4), respectively. For the repeat cesarean section cases, OR for births at 37-37+6 weeks and 38-38+6 weeks was 2.5 (95% CI: 1.1-5.8) and 1.3 (95% CI: 0.6-2.7) respectively. Conclusions Elective cesarean section before 39 weeks of gestation is popular and associated with adverse neonatal outcomes. Elective cesarean section performed after 39-39+6 gestational weeks might decrease the risk of adverse neonatal outcomes.