['The therapeutic value of mediastinal lymph node dissection (LND) for early-stage non-small cell lung cancer (NSCLC) remains controversial. We conducted a retrospective study to investigate the impact of mediastinal LND on survival in patients with stage I NSCLC.', 'Clinical data of patients with stage I NSCLC who were treated with surgical resection during a period of ten years were reviewed. The patients were categorized into lobectomy (or pneumonectomy) combined with mediastinal LND or lymph node sampling (LNS) according to the record of their operative procedures. The Kaplan-Meier method was used for survival analysis. Cox proportional hazards model was used for multivariate analysis.', 'Of the 319 patients who were included in the study, 139 patients received mediastinal LND, while 180 underwent LNS. There was a significant difference in overall survival (OS) between the group with LND and the group with LNS (5-year survival rate: 76.4 % vs. 65.9 %, P = 0.015 by log rank test). Multivariate analysis showed that lymph node dissection (RR = 0.548, 95 %CI: 0.350 - 0.858, P = 0.009), together with the stage, significantly influenced overall survival.'] Does mediastinal lymph node dissection affect survival in patients with stage I non-small cell lung cancer?