Discussions regarding the treatment of stage III non-small cell lung cancer (NSCLC) are still ongoing in the literature. It is important to evaluate the developments in radiotherapy and surgery along with the data in real life regarding stage III NSCLC. The aim of this study is to evaluate the treatment approaches and real-life data in stage IIIA and IIIB local advanced NSCLC. Method: The files of 47 patients with local advanced stage IIIA and IIIB NSCLC, who were followed up in the Gazi University Faculty of Medicine, Medical Oncology Clinic between February 2016 and May 2018, were retrospectively evaluated. Results: As the primary treatment, definitive chemoradiotherapy (CRT) to 27 (57%) patients and surgical treatment to 20 (43%) patients were applied. It was observed that the performance status (p=0.010) of the patients who underwent CRT was statistically significantly worse, active smoking (p=0.033) was higher, and had a more advanced lymph node stage (p=0.052). In the univariate analysis, it was determined that lymph node status (p=0.011), performance status of the patients (p=0.0247), and treatment modality of patients (p=0.001) were the prognostic factors affecting survival. The 1-year overall survival rates and median survival of the patients were 85% and 23 months in the surgical group respectively, and 41% and 10 months in the definitive CRT group. In the multivariate analysis, surgery was found to be a better independent prognostic factor than CRT (HR: 2.72, 95% CI: 1.27-5.82, p=0.010). Conclusions: It was observed that the results of the patients, who were found to be respectable as a result of the clinical experience in stage III NSCLC patient group, were better. The mediastinal lymph node involvement site, especially N3 lymph node site, and the patient performance are among the important factors that determine the prognosis in stage III NSCLC.