The aim of this study was to investigate whether volumetric positron emission tomography (PET) parameters are prognostic predictors in stage III non-small cell lung cancer patients receiving definitive concurrent chemo-radiotherapy (CCRT) with cisplatin/docetaxel. Cases involving definitive CCRT were reviewed retrospectively, and the maximum standardized uptake value, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were calculated. The relationships between these PET parameters and prognosis were analyzed. MTV and TLG were significant predictors of distant metastasis-free survival (DMFS) (p = 0.0003 and 0.0005, respectively) and progression-free survival (PFS) (p = 0.001 and 0.0007, respectively). The three-year DMFS rates in patients with low and high MTV were 13.3% and 64.6%, respectively, and the corresponding values in those with low and high TLG were 13.3% and 65.2%, respectively. The three-year PFS rates in patients with low and high MTV were 13.3% and 57.8%, respectively, and the corresponding values in patients with low and high TLG were 13.3% and 57.8%, respectively. However, MTV and TLG were not predictors of local control or overall sur-vival. We demonstrated that volumetric PET parameters were predictors of patients receiving definitive CCRT. Our findings contradict the findings of previous reports and warrant further research to validate them.