<h3>Purpose/Objective(s)</h3> The role of internal mammary nodal irradiation (IMNI) as a component of regional nodal radiotherapy is a controversial issue in breast radiation oncology with conflicting results presented in recent landmark trials. We thus created a meta-analysis of available data to better ascertain the potential benefit of IMNI. We hypothesize that with the increased power available within a meta-analysis, IMNI will prove to improve overall survival in breast cancer. <h3>Materials/Methods</h3> Four studies (DBCG-IMN 2015, Hennequin <i>et al</i> 2013, KROG 2022, and Stemmer <i>et al</i> 2003) with a total of 5,258 patients (IMNI = 2698, No IMNI = 2560) were meta-analyzed with a primary end point of overall survival (OS). Secondary endpoints were disease free survival (DFS), breast cancer mortality (BCM), and distant metastasis free survival (DMFS). Subgroup analyses were performed for medial/central tumor location, and pN+ versus pN0 status. Fixed-effect model was used if there was no heterogeneity, random-effects model otherwise. <h3>Results</h3> Pooled results showed IMNI significantly improved OS for all comers (HR 0.87, 95% CI 0.79-0.97, <i>p</i>=0.01), as well as subgroups of pN+ with medial/central tumor location (HR 0.80, 95% CI 0.68-0.94, <i>p</i>=0.005) and pN+ with lateral tumor location (HR 0.86, 95% CI 0.745-0.995, <i>p</i>=0.04). There was no significant difference in OS for subgroups of pN0 and medial/central tumor location. Secondary endpoints of DFS (HR 0.90, 95% CI 0.82-0.99, <i>p</i>=0.03), BCM (HR 0.83, 95% CI 0.73-0.96, <i>p</i>=0.01), and DMFS (HR 0.88, 95% CI 0.78-0.99, <i>p</i>=0.04) were all similarly improved with IMNI. <h3>Conclusion</h3> Inclusion of IMNI to regional nodes improves OS in breast cancer, with the strongest effect noted in pN+ patients with medial/central tumor location.