A long acting local anesthetic; ropivacaine and a synthetic opioid ; tramadol were used to improve pain relief and decrease postoperative systemic analgesic requirement after total thyroidectomy in patients with thyroid cancer. The study also assesses the effect of local infiltration with ropivacaine and tramadol on plasma catecholamine levels. Methods: Ninety six patients underwent thyroid surgery were randomly assigned to 3 groups. Before skin closure, tissues were infiltrated 10 ml of ropivacaine 0.75% plus 5 ml saline in Group R, with 1.5 mg/kg of tramadol in 15 ml saline in Group T, and with 15 ml containing 10 mL ropivacaine 0.75% plus tramadol 1.5mg/kg in Group RT. Plasma epinephrine and nor-epinephrine were recorded at preoperative (0), 1, 5, 15, 30min, 1, 2 and 4 h postoperative. Pain scores at min, 0.1/2, 1,2,4,6, 12, 18, and 24 hr post-operatively; time to first analgesic, number and % of patients requiring rescue analgesia, number of rescue analgesia and total dose of analgesic were recorded. Results; The pain scores in group RT were significantly lower in the first 24 hours than in groups R and T. Time to first analgesic (hrs) in group RT was significantly more than in either group R or group T. The percentage of patients in group RT requiring rescue analgesia was significantly less than the percentage of patients in other groups. Also, the numbers of rescue analgesia requests and the cumulative 24 h analgesic consumption were significantly smaller in group RT than other groups. The plasma epinephrine and nor-epinephrine increased significantly in three groups at 5 and 15 min when compared with the baseline then returned to near baseline value at 30 min 1,2 and 4 hrs. There was significant decrease in plasma concentration of epinephrine and nor-epinephrine in group RT than R or T groups. The aim of this study is to evaluate wound infiltration with ropivacaine, tramadol or their combination on plasma catecholamine levels and post-operative pain following thyroid surgery.