Introduction : Laparoscopy is a popular in outpatient gynecology. The most common complication associated with this procedure is postoperative nausea and vomiting (PONV) which sometimes requires patient hospitalization. In this prospective randomised double blinded controlled study, we evaluated prophylactic efficacy in reducing PONV by using droperidol (0.02 mg/kg IV) or dexamethasone (0.15 mg/kg IV) compared with a placebo. Methods : Eighty-four outpatients, age 15-45, ASA Class I-II were divided into three groups at random (28 patients/group). Five minutes after induction and intubation, we gave the studied drug; droperidol, dexamethasone or saline and then maintained anesthesia under balanced technique. Results : The incidence of PONV in the droperidol group was less than the placebo group at 30 min (P=0.033) and less than the dexamethasone group at 60 and 90 min (P=0.035 and 0.048 respectively). The overall incidence of PONV in the droperidol group was less than the dexamethasone and placebo groups (32.1% compared with 46.4% and 53.5% respectively). In patients with a history of PONV or motion sickness, the incidence of PONV in the droperidol group was also less than the dexamethasone and placebo groups. The droperidol gropu had sedation scores higher than the dexamethasone and placebo groups only at 60 min. (P=0.04 and 0.032 respectively). There was no nifference in the incidence of PONV at 120 and 180 min in the postanesthetic care unit (PACU) and 24 hr at home between all three study groups. The number of patients who had to be admitted due to severe nausea and vomiting were three in the placebo group and one patient in the dexamethasone group. Conclusion : Droperidol is more effective in prephylaxis of early PONV than dexamethasone or a placebo with sedation occurring only at 60 min in gynecologic laparoscopic outpatients.