Background: The aim of this study was to evaluate the preventive effect of propofol on postoperative nausea and vomiting (PONV) following general anesthesia to the patients having oral and maxillofacial surgery. Methods: In a prospective, randomized. case-controlled study. 200 patients were divided into two groups (n = 100 in each). In propofol (P) group, patients received 0.5 mg/kg of propofol intravenously at the end of anesthesia. In control (C) group, no antiemetics was given. Emetic symptoms like nausea, retching and vomiting were assessed by a blind nurse at 1 hour and at 24 hours after anesthesia respectively. Also level of sedation was checked by a blind anesthesiologist at 1 hour after anesthesia. Results: There were no significant differences in frequencies of nausea, retching and vomiting between C group and P group at 1 hour after anesthesia. However, nausea, retching and vomiting were all decreased in P group compared with C group at 24 hours after anesthesia (P < 0.05). Also there was no significant difference in level of sedation at 1 hour after anesthesia between C group and P group (P > 0.05). Conclusions: From the results, prophylactic use of subhypnotic dose of propofol could be effective for preventing PONV without change in level of sedation to the patients undergoing general anesthesia for oral and maxillofaical surgery.