BACKGROUND: Laparoscopic gynecologic surgery is a standard procedure today for its small skin incision and short hospital admission stay. However pneumoperitoneum (PP) and Trendelenberg position induce adverse effects in hemodynamics and pulmonary gas exchange. The purpose of this study is to evaluate the effects of propofol compared with enflurane for pulmonary gas exchange in the Trendelenberg position and pneumoperitoneum. METHODS: Twenty women were randomly allocated to either the enflurane (n = 10) or propofol (n = 10) with fentanyl-N2O/O2 anesthesia. PaCO2, PaO2, PETCO2 were checked at pre-PP, 10 min after PP, 30 min after PP, and 10 min after CO2 deflation. In addition the Vd/Vt ratio was calculated according to the Bohr equation. Vital sign and peak airway pressure were checked at each stage. RESULTS: PaCO2 and PETCO2 increased and PaO2 decreased significantly during PP in both groups. Vd/Vt increased significantly in the enflurane group at 30 min after PP. Peak airway pressure increased significantly in both groups. Blood preassure and heart rate were not changed significantly. All of the parameters were not significantly different between groups. CONCLSIONS: Propofol compared with enflurane did not show any advantage in gas exchange during gynecologic laparoscopic surgery under Trendelenberg position and PP.