Background: Endothelial growth factor receptor (EGFR)-mutant lung adenocarcinoma displays diverse responses to tyrosine kinase inhibitor therapy. Concurrent somatic alterations represent different biological substantial proportion of patients with EGFR mutations and impacts their prognosis. Methods: We conducted this retrospective study to clarify the comprehensive concurrent genetic alterations of TP53 and RB1 and tumor mutational burden (TMB) in 712 EGFR-mutant or EGFR-wild type lung adenocarcinoma by next generation sequencing-based gene panel tests. Results: EGFR was the most frequently mutated gene altered in 58.0% (413/712) of lung adenocarcinoma, followed by TP53 altered in 56.7%, KRAS altered in 13.3%, and RBM10 altered in 11.2% of all patients. Concurrent genetic alteration of TP53 and RB1 is more likely to be found in EGFR-mutant patients than in EGFR-wild type patients, with a frequency of 11.4% (45/413) and 4.3% (13/299), respectively (p = 0.003). However, the frequency of TP53 and RB1 concurrent alteration was similar in lung cancer with sensitive EGFR mutation compared to those with non-sensitive mutation (10.5% versus 11.6%). TP53 mutation was most frequently found in patients with RB1 mutation (58/61), irrespective of EGFR mutational status. Furthermore, significant difference was found regarding median TMB in patients with mutant EGFR compared to those with non-mutant EGFR (3.8 versus 4.3; p < 0.001). Median TMB was higher for patients with TP53 and RB1 concurrent alteration than those without concurrent alteration in all patients (5.4 versus 4.3, p = 0.018). Conclusions: Our data showed that high prevalence of concurrent somatic alterations of TP53 and RB1 genes among lung adenocarcinoma patients with EGFR mutations, which might help understand several key biological processes and develop potential therapeutic strategies.