This study was undertaken to evaluate the feasibility of thoracic epidural anesthesia as an alternative technique to general anesthesia in patients undergoing cardiac surgery under cardiopulmonary bypass. This prospective study was conducted in a tertiary referral hospital. Seventeen patients underwent cardiac surgical procedures requiring cardiopulmonary bypass without general anesthesia under thoracic epidural anesthesia from February to May 2004. An epidural catheter was inserted at any of intervertebral spaces from C7 to T2 on the day before surgery. Subsequently, cardiac surgery was performed under normothermic cardiopulmonary bypass, during which the patients remained conscious. The types of surgery included closure of atrial septal defects, valve replacements, and combined bypass surgery and valve replacements. Approach to the heart was obtained through midsternotomy. Anticoagulation was achieved with 300 units/kg of heparin. Normothermic cardiopulmonary bypass was initiated slowly during the course of 10 to 15 min. Nonpulsatile flow was administered using centrifugal pump and mean perfusion pressure was maintained in the range of 70-80 mmHg. The planned surgical procedure could be performed in all the patients. Soon after establishing cardiopulmonary bypass, the patients developed apnea, which reverted to normalcy a few minutes after disconnection of cardiopulmonary bypass. The mean time for cardiopulmonary bypass was 102 +/- 28 min, aortic cross clamp time was 58 +/- 28 min, and the total duration of surgery was 229 +/- 64 min. None of the patients required conversion to general anesthesia. There was no mortality or morbidity in this series and to our knowledge our series is the first such. Cardiac surgical procedures requiring cardiopulmonary bypass may be conducted under thoracic epidural anesthesia, without endotracheal general anesthesia.