The usefulness of continuous monitoring of central venous oxygen saturation (SCvO 2 ) in comparison with the capnogram during cardiopulmonary resuscitation (CPR) was demonstrated in a cardiac arrest patient. SCvO 2 and end-tidal carbon dioxide (ETCO 2 ) decreased following cessation of chest compression or increased during recovery of systemic circulation. During the complete stasis of systemic circulation, when defibrillation was done, SCvO 2 did not change, while ETCO 2 gradually decreased. However the larger decrease in SCvO 2 temporally occurred when chest compression was resumed. And also the SCvO 2 monitoring had great advantage to detecting peripheral tissue oxygenation. SCvO 2 seems to be no less accurate and reliable monitoring than the capnogram during CPR procedures. Since the capnogram is non-invasively and easily used in cardiac arrest patients, SCvO 2 monitoring combined with the capnogram is a more preferable method for assessing the efficacy of ongoing CPR.