The Gustave Roussy Immune score (GRIm-Score) emerges as a novel prognostic scoring system for patient selection in phase I trials testing targeted immunotherapy for advanced-stage cancer. We tried to assess potential prognostic roles of preoperative GRIm-Score in patients undergoing video-assisted thoracoscopic surgery (VATS) lobectomy for stage I-II non-small-cell lung cancer (NSCLC) by propensity score-matching (PSM) analysis. This PSM-based analysis was performed on our single-center prospectively-maintained database between January 2014 and October 2015. A Kaplan-Meier survival analysis using the log-rank test was used to distinguish differences in both overall survival (OS) and disease-free survival (DFS) between the patients stratified by preoperative GRIm-Score. Multivariable Cox-proportional hazards regression analysis and PSM analysis were both carried out to determine the final independent prognostic parameters. There were 405 patients with surgically resectable stage I-II NSCLC included. Both OS and DFS were significantly shortened along with each number increase in the GRIm-Score group, showing a step-wise fashion. Such strong correlations between preoperative GRIm-Score estimated by a modified 3-category risk scale and survival outcomes still remained validated after PSM analysis. In addition, this GRIm-Score held the superior discriminatory power for predicting both OS and DFS to the other peripheral blood biomarkers. Multivariable analyses on the entire cohort and the PSM cohort demonstrated that GRIm-Score based on a 3-category risk assessment scale could be independently predictive of both OS and DFS. The GRIm-Score tool can also serve as an effective and noninvasive marker to optimize prognostic prediction for surgically resectable stage I-II NSCLC. Copyright © 2020 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.