Background:Postoperative nausea and vomiting (PONV) is a common complication after general anesthesia in patients undergoing elective lower abdominal surgery. We aimed to compare the effect of a sub hypnotic dose of Propofol in the prevention of PONV after lower abdominal surgery with that of the conventional antiemetic drug Metoclopramide.Materials and Methods:In this prospective, randomized, double-blind, placebo-controlled study, 104 patients with American Society of Anesthesiologists (ASA) class I or II status, aged 18–65 years, and undergoing elective lower abdominal surgery were randomized to one of four groups (n = 26 each). The patients in the four groups were administered intravenously Propofol 20 mg (G1), Propofol 30 mg (G2), Metoclopramide 10 mg (G3), and placebo (G4), 15 min before skin closure. All episodes of PONV during the first 24 h after anesthesia were recorded by an investigator who was blinded to treatment assignment.Results:There were no significant differences between the treatment groups with regard to their gender, age, ASA class, duration of surgery, duration of recovery time and hospital stay, and also body mass index (BMI) (P > 0.05). The prevalence of PONV 0-6 h after anesthesia was 23.08% with Propofol 20 mg (P = 0.005), 15.38% with Propofol 30 mg (P = 0.016), 15.38% with Metoclopramide 10 mg (P = 0.016), compared to 30.77% with placebo (P = 0.005).Conclusions:Administration of a subhypnotic dose of Propofol (30 mg) was found to be as effective as 10 mg Metoclopramide in reducing the incidence and severity of PONV in adult patients undergoing elective lower abdominal surgeries under Isoflurane-based anesthesia in the early postoperative period.