Background <p>Postoperative nausea and vomiting (PONV) is a relatively common complication of general anesthesia. We encountered PONV in pediatric patients after dental and oral maxillofacial surgeries under general anesthesia. In particular, there is a higher incidence of PONV due to bleeding of the oral cavity and aspiration of gastric contents. In this study, we retrospectively investigated the risk factors of PONV on the first postoperative day in pediatric patients.</p> Methods <p>This study was approved by the Kyushu University Clinical Research Ethics Committee and was conducted retrospectively, so informed consent for participation was not obtained. The anesthesia records of patients (aged 0–12 years) were retrospectively reviewed. The patient underwent dental and oral maxillofacial surgeries. The patients’ background, anesthesia time, use of anesthetic drugs, nitrous oxide (N₂O), history of PONV, motion sickness, disability, and time to oral intake were investigated. In the univariate analysis, Fisher’s exact and χ2 tests were used, and a multivariable analysis was performed using stepwise logistic regression to determine the risk factors of PONV.</p> Results <p>A total of 589 patients were enrolled, with a mean age of 5.6 ± 2.8 years, and were divided into two groups based on the presence or absence of PONV. Eighty-six patients (14.6%) complained of PONV. The occurrence of PONV was correlated with age, anesthesia time, fentanyl, N₂O, history of PONV, and motion sickness. Fentanyl was the highest risk factor (odds ratio = 1.76; 95% confidence interval = 1.33–2.32).</p> Conclusion <p>Our findings suggest that the administration of fentanyl may be associated with an increased risk of PONV in pediatric patients undergoing dental and oral and maxillofacial surgery under general anesthesia.</p>