We introduced thoracoscopic esophagectomy with extended lymphadenectomy for reduction of respiratory dysfunction and less surgical intervention in July 1995. In this study, we investigated the changes in serum interleukin-6 (IL-6) and interleukin-1 receptor antagonist (IL-1ra) levels in 8 patients (TS Group) who underwent thoracoscopic esophagectomy with extended lymphadenectomy and compared them with the changes in patients who underwent conventional thoracotomy (CT Group). The duration of the operation and intrathoracic procedure in the TS group were significantly longer than in the CT group. However, the amount of blood loss and intrathoracic blood loss of the TS group were not significantly higher than in the CT group. The number of dissected lymph nodes was not significantly larger. The serum IL-6 levels reached maximum levels 3 hours from the end of operation. In the TS group, the changes in IL-6 levels were significantly larger (p < 0.05). On the other hand, the changes in CRP levels were also significantly larger (p < 0.01). Significant correlation was observed between the duration of the intrathoracic procedure and the maximum levels of IL-6. On the other hand, serum IL-1ra levels were not significantly. At present, these results suggest that the surgical intervention of thoracoscopic esophagectomy are more larger than that of conventional thoracotomy. We think that the length of intrathoracic procedure of thoracoscopic esophagectomy may make more large surgical stress.