ABSTRACT Aim: To investigate the effect of modern postoperative radiotherapy (PORT) ) on the 5-year overall survival (OS) in non-small cell lung cancer (NSCLC) patients with persistent N2 disease after induction chemotherapy. Methods: Patients with resectable pathologically proven N2 NSCLC who received induction chemotherapy followed by surgery were selected from a prospective database from September 1999 to December 2010. 103 patients without progressive disease after chemotherapy underwent resection. 95% of patients were staged with FDG-PET and 85% underwent brain imaging. In case of incomplete resection or persistent ypN2 status, patients received 3D-PORT (n = 53) to a dose of 50-66 Gy in 2 Gy fractions. Patients with a complete resection and with nodal downstaging to ypN0 or ypN1 did not receive PORT. Results: Median follow up time was 46.3 months. For the operated group (n = 103) the 5-year OS was 31.3%, relapse free survival (RFS) 29.8%, and the cumulative local recurrence (LR) rate 51.0%. Multivariate analysis identified as significant co-variables for 5-year OS: PORT (relative risk (RR) = 0.441, p = 0.017), downstaging after chemotherapy (RR = 0.478, p = 0.030) and completeness of resection (RR = 2.051, p = Conclusions: Although patients having received PORT were a group with adverse prognostic factors, PORT could improve survival for patients with stage IIIA NSCLC and ypN0/1 or R1/R2. This needs to be investigated further in a prospective randomized trial. As LR remains high also in the ypN0 and ypN1 groups, PORT is worth to be investigated or considered in these patients as well. Disclosure: All authors have declared no conflicts of interest.