Background: Nausea and vomiting after a cesarean section (CS) are among the common side effects that cause dissatisfaction among doctors. The aim of this study was to compare the effects of intravenous midazolam and ondansetron on the reduction of nausea and vomiting after spinal anesthesia in CS. Methods: This double-blind clinical trial study was conducted on CS candidates who underwent spinal anesthesia (N=80). After spinal anesthesia, the patients were randomly divided into two groups. Midazolam was administered to one group and ondansetron to the other group. The severity of nausea, the severity of vomiting, and the degree of satisfaction were recorded during surgery and recovery. Results: No significant difference was observed between the two groups in terms of the severity of nausea and vomiting. In addition, the results demonstrated that the level of satisfaction in the midazolam group was higher than that in the ondansetron group, but this difference was not statistically significant (P<0.05). Conclusion: The results of this study showed that midazolam can reduce nausea and vomiting. On the other hand, the results confirmed that both ondansetron and midazolam can have the same effects on reducing nausea and vomiting.