Purpose <p>Segmentectomy has become the new standard of care for selected patients with stage IA1-2 non-small cell lung cancer (NSCLC). For stage IA3 NSCLC, lobectomy is indicated. This study aims to compare the outcome after segmentectomy and lobectomy in patients with stage IA3 NSCLC.</p> Methods <p>We retrospectively reviewed all patients undergoing surgery for NSCLC in our center between 2013 and 2023. We identified all patients who underwent segmentectomy or lobectomy for pathological stage IA3 tumors. Survival was calculated from the date of surgery until last follow- up. Univariate analysis was performed to study the impact on overall survival (OS) and disease-free survival (DFS) of clinical variables.</p> Results <p>We identified fifty-nine patients undergoing surgery for stage IA3 NSCLC. Twenty- seven (28%) patients underwent segmentectomy and sixty-eight (72%) patients underwent lobectomy. Median age was 68 years (47–85). Median FEV1 was 74% (39–140), median DLCO was 67% (28–128). Surgery was performed by VATS in most cases (91%). There was no difference in age and lung function between the lobectomy and segmentectomy groups. Five-year OS was 67%. 5-year DFS was 63%. Five-year DFS was significantly worse in patients who underwent segmentectomy compared to lobectomy (37% vs. 72%, <i>p</i> = 0.040). There was no difference in 5-year OS (56% vs. 69%, <i>p</i> = 0.56).</p> Conclusion <p>Segmentectomy is associated with significantly worse disease-free survival compared to lobectomy in our cohort of patients with stage IA3 NSCLC.</p>