The purpose of this study was to evaluate the effect of postural change on hemodynamics under halothane-N2O-O2 anesthesia. The authors measured heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), mean pulmonary artery pressure (PVP), and cardiac index (C1) on supine position (baseline), and after a postural change to the lithotomy, head up tilt (5, 10, 15 degress) and head down tilt (5, 10, 15 degrees) positions in 10 healthy subjects. The results were as follows: 1) After a postural change to the lithotomy position, all hemodynamic variables revealed no changes. 2) After a change to the head up position, MAP, CVP, PAP, PCWP, and CI decreased significantly, while HR remained unchanged. 3) After a change to the head down position, CVP, PAP, PCWP, and CI increased and HR decreased significantly, while MAP remained unchanged. From the above results, it might be concluded that a down ward tilt of 10 degrees is most the appropriate position to restore hemodynamics in the presence of cardiovascular instability.