Postoperative pain may be associated with shallow breathing, inability to cough, and reduction in spirometric values which lead to restrictive pattern of ventilation with hypoxemia and/or hypercarbia. Therefore, postoperative pain should be managed with appropriate methods. The authors have usually performed intraoperative intercostal nerve block with 0.25% bupivacaine hydrochloride to alleviate postoperative thoracotomy pain. A 21 years old male patient developed sudden hypotension and severe bradycardia 1 minute following the intraoperative 4th, 5th, 6th intercostal nerve block with a total of 10 ml of 0.25% bupivacaine hydrochloride, who was treated by ephedrine with success. The authors discuss the possible causes of sudden hypotension and severe bradycardia in detail.