This study evaluated the potential role of (18)F-fluoro-2-deoxy-glucose (FDG) uptake by primary tumors and N2 nodes on positron emission tomography (PET) in patients with stage IIIA N2 non-small-cell lung cancer (NSCLC). We retrospectively analyzed PET scans of 57 NSCLC patients who received surgical resection and proved pathologically to have stage IIIA N2 disease between January 2000 and April 2005. On each patient's PET scan, FDG uptake by the primary tumor and N2 nodes was evaluated using the maximum standardized uptake value (SUV). The SUV of the primary tumor (SUVt) and the highest value of the N2 nodes (SUVn) in each patient were treated as continuous variables for initial analysis. The SUVn and T stage (T1-2 vs. T3) were significant prognostic factors in univariate analysis (P=0.004 and 0.017, respectively), but the SUVt was not. Adjusted for the size of the N2 node (<or=1cm vs.>1cm), SUVt, and T stage (T1-2 vs. T3), the SUVn was associated with survival (P=0.019). Patients were divided into those with a low and high SUVn using a cutoff value. Controlling for the size of N2 nodes and T stages, patients with a low SUVn showed a tendency for prolonged survival (P=0.053). These results suggest that FDG uptake by the N2 node may predict survival of patients with stage IIIA N2 NSCLC.