ObjectiveTo evaluate the value of postoperative radiotherapy (PORT) in patients with stage ⅢA-N2 non-small cell lung cancer who received complete resection and chemotherapy. MethodsPatients with stage ⅢA-N2 non-small cell lung cancer who received complete resection and chemotherapy were chosen from the SEER Research Plus Database (17 Registries, November 2021Submission [2000-2019]). The patients were divided into a PORT group and a non-PORT group according to whether the PORT was used. To balance baseline characteristics between non-PORT and PORT groups, R software was used to conduct a propensity score matching (PSM) with a ratio of 1 : 1 and a matching tolerance of 0.01. Both the Cox regression analysis and Kaplan-Meier survival analysis were conducted to evaluate the value of PORT in patients with stage ⅢA-N2 non-small cell lung cancer who received complete resection and chemotherapy in terms of overall survival (OS) and disease-specific survival (DSS). ResultsIn total, 2468 patients with stage ⅢA-N2 non-small cell lung cancer were enrolled, including 1078 males and 1390 females with a median age of 65 (58-71) years. There were 1336 patients in the PORT group, and 1132 patients in the non-PORT group. Cox regression analysis showed that PORT was not significantly associated with OS (multivariate analysis: HR=0.951, 95%CI 0.859-1.054, P=0.338) and DSS (multivariate analysis: HR=0.914, 95%CI 0.816-1.025, P=0.123) in patients with stage ⅢA-N2 non-small cell lung cancer who received complete resection and chemotherapy. No statistical difference was found in the OS or DSS between non-PORT group and PORT group before and after PSM analysis (P＞0.05). ConclusionPORT does not have a survival benefit for patients with stage ⅢA-N2 non-small cell lung cancer who received complete resection and chemotherapy.