Background: Of patients with non small cell lung cancer (NSCLC), around one third are locally advanced at the time of diagnosis. Because only a proprotion of stage III patients can be cured by surgery, in order to improve the outcomes, sequential or concurrent chemoradiation, or concurrent chemoradiation with induction or consolidation is offered to the patients with locally advanced NSCLC. Today, PET combined with computerized tomography (PET-CT) is accepted as the most sensitive technique for detecting mediastinal lymph node and extracranial metastases from NSCLC. We aimed to compare PET-CT and conventional staging procedures for decisions regarding curative treatment of locally advanced NSCLC. Materials and Methods: A total of 168 consecutive patients were included from Acibadem Kayseri Hospital, Acibadem Adana Hospital and Kayseri Research and Training Hospital in this study. Results: While the median PFS was $13.0{pm}1.9$ months in the PET-CT group, it was only $6.0{pm}0.9$ in the others (p<0.001). The median OS values were $20.5{pm}15.6$ and $11.5{pm}1.5$ months, respectively (p<0.001). Discussion: As a result, we found that staging with PET CT has better results in terms of survival staging. This superiority leads to survival advantage in patients with locally advanced NSCLC.