BACKGROUND: Pelviscopic techniques have rapidly increased in therapeutic procedures as well as diagnostic procedures because of the many benefits associated with much smaller incisions than traditional open techniques. But the deliberate pneumoperitoneum with carbon dioxide during pelviscopic surgery may cause some problems-hypercarbia, pneumomentum, subcutaneous or mediastinal emphysema, pneumothorax, hypoxemia, hypotension, cardiovascular collapse and cardiac dysrhythmia. METHOD: We observed the changes of blood pressure (systolic, mean, diastolic), pulse rate, PaCO2, PaO2, peak inspiratory airway pressure and expired tidal volume at 10 minute after induction of general anesthesia (control value), 30 minutes and 60 minutes after insufflation of CO2 and Trendelenburg position. RESULTS: The blood pressure, PaCO2 and peak inspiratory airway pressure were increased significantly than control values (p<0.05). The changes of pulse rate and expired tidal volume were not statistically significant in comparison to control values. The PaO2 was decreased significantly (p<0.05). CONCLUSION: To minimize the risk of CO2 retension and unstability of cardiovascular system during pelviscopy under the Trendelenburg position, we must monitor the vital signs and the arterial blood gas status continuously and carefully.