Venous air embolism(VAE) can occur by the entry of air into open veins, being facilitated if the operative field is above the level of the heart. Among the many diagnostic methods, precordial ultrasonic Doppler is currently the more sensitive. Thus we have attempted to define the incidence of VAE using this device. 103 ASA physical status 1 or 2 parturients undergoing Cesarean section with general anesthesia in 73 parturients and epidural anesthesia in 30 parturients were studied with the ultrasonic Doppler transducer placed parasternally over the 4th right intercostal space. Total incidence of venous emboli was 31%(32/103) during surgery. In some parturients, embolism occurred more than once during operation and leaded to total 45 episodes of venous emboli. The incidence of venous emboli was 26%(19/73 ) during general anesthesia and 43.3%(13/30 ) during epidural anesthesia. No statistical difference existed in the incidence of venous emboli detected related to the type of anesthesia. Among the 45 episodes of venous emboli, 19 episodes(42.2%) were detected during repair of the hysterotomy. As even small air bubbles in the circulation are potentially harmful especially in patent foramen ovale and emboli events may occur at risk cases involving profound hypovolemia, abruptio placenta, or placenta previa, clinically insignificant venous air emboli, although low, is still worrisome. Thus above the cases, the use of additional precordial Doppler monitoring may be considered during cesarean section to detect VAE promptly, efficiently.(Korean J Anesthesiol 1995; 29: 858-862)