Background: the aim of this study was to investigate the prognostic value of ¹⁸Fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) parameters in both overall survival and progression-free survival in Stage I-III non-small cell lung cancer (NSCLC). Materials and Methods: In this retrospective study, 267 patients who were diagnosed as Stage I-III non-small cell lung cancer and had undergone FDG-PET/CT imaging before treatment were included. PET/CT parameters, maximum and mean standardized uptake values (SUVmax and SUVmean), metabolic tumor volume (MTV), total lesional glycolysis (TLG), and maximum tumor-to-blood standard uptake ratio (SURmax) were calculated. Analyses were performed to evaluate the ability of PET parameters to predict recurrence and death as well as to determine prognostic value. Results: In predicting both mortality and progression, the area under the ROC curve (AUC) value was highest for TLG (AUC: 0.717, 0.692 respectively). Overall survival was lower in patients with TLG> 214, and progression-free survival was lower in patients with TLG> 194. All PET parameters had a prognostic value in univariate analysis. Age, N1 stage and SUVmean were independent prognostic factors in multivariate analysis. Conclusion: In predicting death and progression, TLG had the highest predictive value. Age and N1 stage were independent prognostic factors in multivariate analysis, while SUVmean was the most valuable independent prognostic factor.