Purpose of investigation: To explore the effect of delayed umbilical cord clamping in cesarean section on outcomes of mothers and newborns. Materials and Methods: A total of 338 pregnant women under cesarean section were randomly divided into two groups: study group with delayed umbilical cord clamping after pulsation loss, and control group with early clamping within 60 seconds after birth. Results: There were no significant differences in hemoglobin and hematocrit in newborn cord blood, the highest bilirubin after birth, Apgar scores at one and five minutes after birth, and in the occurrence of neonatal hyperbilirubinemia or application of phototherapy. There were significant differences in placental residual blood, the amount of postpartum bleeding, hemoglobin and hematocrit in newborn heel blood, and the rate of neonatal resuscitation after ten minutes in both groups. Conclusion: Umbilical cord clamping should be employed after pulsation loss to avoid adverse effect of early clamping.