Epidural anesthesia is a popular regional anesthetic technique for total hip replacement (THR). It s benefits are reduced blood loss, less need for transfusion, and decreased chance of deep vein thrombosis, and if necessary, it provides longstanding postoperative analgesia with small dose of epidural narcotics through indwelling epidural catheter. The wellknown cardiovascular effects are bradycardia and hypotension according to the degree of sympathetic blockade. These occur usually early in the anesthetic period and the course is benign and are easily treated. We report a case of sudden extreme bradycardia and hypotension during THR under epidural anesthesia that was not associated with hypoxemia, obvious respiratory depression, or systemic toxic reaction. It is concluded that the most likely cause would be a sudden large increase in vagal activity which results from marked reduction in venous return and inadequate oxygenation of myocardium with the assumption of prolonged iatrogenic hemodilution and undercorrected hypovolemia. The patient who receives epidural anesthesia should require constant monitoring and vigilance throughout all procedure.