Neoadjuvant combined radiochemotherapy followed by definitive tumor resection improved survival in patients with locally advanced non-small cell lung cancer (NSCLC). Fifty-four patients (NSCLC IIIa + IIIb) were treated with combined radiochemotherapy within a phase I/II study. Twenty-six patients had been resected after combined neoadjuvant treatment and this group was evaluated concerning long-term survival. The median survival for patients with stage IIIa tumor was calculated to be 26 months and 13 months for patients with IIIb status. Patients with no viable tumor cells in the mediastinal lymph nodes had a significantly better survival probability than patients with residual microscopic lymph node disease (p=0.038). Patients with no viable tumor cells had a 1-year (2-year) survival rate of 100% (60%) versus 58% (42%) for patients with residual microscopic tumor in the mediastinal nodes. No significant difference between the N1- and the N2-status was seen. Hence, response to neo-adjuvant radiochemotherapy seems to be an additional important prognostic factor in patients with advanced NSCLC.