Objective To evaluate the effect of elective repeat cesarean section on the maternal and neonatal outcomes. Methods A retrospective clinicand hospital-based survey was designed for comparing the maternal and neonatal outcomes of elective repeat cesarean section [RCS group （one previous cesarean section） and MRCS group （two or more previous cesarean sections）] and primary cesarean section （FCS group） at Peking Union Medical College Hospital from January 1998 to December 2007. Results The incidence of repeat cesarean section increased from 1.26% to 7.32%. The mean gestational age at delivery in RCS group （38.1±1.8 weeks） and MRCS group （37.3±2.5 weeks） were significantly shorter than that in FCS group （38.9±2.1 weeks

all P<0.01）. The incidence of complication was 33.8% and 33.3% in RCS group and MRCS group respectively

and was significantly higher than that in FCS group （7.9%

P<0.05）. Dense adhesion （13.5% vs. 0.4%

OR=7.156

95% CI: 1.7-30.7

P<0.01） and uterine rupture （1.0% vs. 0

P<0.05） were commoner in RCS group compared with FCS group. Neonatal morbidity was similar among three groups （P>0.05）. Conclusions Repeat cesarean section is associated with more complicated surgery technique and increased frequency of maternal morbidity. However

the incidence of neonatal morbidity is similar to primary cesarean section.