In the setting of obstetric emergencies for pregnant women or their fetuses, prompt delivery should be performed. While no clear absolute time threshold has been demonstrated to be a specific standard of care, many guidelines have recommended that the decision-to-delivery interval (DDI) be kept to less than 30 minutes when emergent cesarean section (ECS) is performed. However, an emphasis on shortening the DDI is a common issue at most hospitals. Many steps need to be performed before the commencement of a cesarean section. Thus, in order to improve the maternal and neonatal prognosis, regular simulation training for emergent cesarean delivery was conducted beginning in March 2014. The present study measured the effects of this simulation training for medical staff on the DDI and the results of a shortened DDI on the maternal and neonatal outcomes. Specifically, data from November 2011 to August 2016 at Nagoya University Hospital, Nagoya, Japan, were collected. As the simulation training was performed in March 2014, the study population was divided into 2 groups: a pretraining group (November 2011-March 2014, 29 months) and a posttraining group (April 2014-August 2016, 29 months). The DDI and maternal and neonatal outcomes were compared between the 2 groups. As a result of introducing simulation training, the DDI was significantly shortened (15.9 vs 22.7 minutes; P = 0.009). In 82.9% of posttraining cases (29/35), the DDI was 20 minutes or less. The study's findings indicated that simulation training was effective for improving communication shortening the period of patient transfer from the delivery room to the operating room when an ECS is needed. The decision to enter the operating room interval was the most important part of shortening the DDI (6.7 vs 10.9 minutes; P = 0.003). During simulation training, it was determined that the major problem was identifying the fastest route to transfer patients to the operating room. As a result, the most suitable transfer route was identified, and the simulation training was performed many times. A new and unique finding was that the most important action to reduce time was pushing the elevator button quickly. In addition, the study found that the mean umbilical artery pH was significantly improved (7.27 vs 7.08, P = 0.012) by simulation training in "irreversible" cases, such as those with placental abruption or uterine rupture, which can directly affect an adverse neonatal outcome. Therefore, simulation training to shorten the DDI may contribute to improving the neonatal outcome in these "irreversible" cases. However, the study found that umbilical artery pH was not statistically significantly improved in "reversible" cases with transient phenomena. In the posttraining group, there was no correlation between maternal adverse outcomes, such as anemia, blood transfusion, wound infection, and hematoma. In conclusion, the DDI was significantly shortened by introducing simulation training. Simulation training was shown to be effective for improving communication among relevant staff members and shortening the time period for patient transfer from the delivery room to operating room when an ECS is needed. The study also demonstrated a beneficial effect of the simulation training on umbilical artery pH in "irreversible" cases without increasing the frequency of an adverse maternal outcome.