Anesthesiologists have routinely administered supplementary oxygen to prevent maternal hypoxemia and improve fetal oxygenation during cesarean delivery under spinal anesthesia. Some reports have indicated an increase in fetal free radicals due to prophylactic oxygen administration. The risk factors for hypoxemia during cesarean delivery still remain unclear. Therefore, in this retrospective study, we investigated the incidence of intraoperative hypoxemia and its associated risk factors in 155 patients receiving spinal anesthesia for cesarean delivery. Our study demonstrated that the incidence of intraoperative hypoxemia was high（ 32.3%） in patients receiving spinal anesthesia for cesarean in the absence of supplemental oxygen. It also indicated that spinal block levels higher than T3 or more were associated with intraoperative hypoxemia. Therefore, it is important to carefully observe parturients intraoperatively and prepare to promptly administer oxygen and other treatments if necessary.