Mammalian SWI/SNF complexes are ATP-dependent chromatin remodelers composed of varying combinations of subunits that, together, fine-tune transcriptional regulation and genome integrity. SWI/SNF complex subunits have been identified as major targets of mutations in several tumor types suggesting a relevant role in tumorigenesis. However, there is a lack of comprehensive studies of the whole SWI/SNF complex in lung adenocarcinoma (LUAD). Here, we combined genomic, transcriptomic, and proteomic approaches to identify which SWI/SNF subunits are present in lung cells, as well as their mutational status, mRNA levels, and protein levels in LUAD. For these purposes, we combined data from LUAD primary tumors, normal lung and LUAD cell lines, and external LUAD data from The Cancer Genome Atlas. Importantly, we found that mutations in the SWI/SNF complex in LUAD not only present a high incidence but we also observed that only the mutational status of the SWI/SNF complex and not the mutations in any of the top ten LUAD driver genes is associated with poorer overall survival in LUAD patients. Furthermore, we showed that the expression of the SWI/SNF complex in LUAD suffers an overall repression that cannot be explained exclusively by genetic alterations. Based on our findings, we propose that SWI/SNF-mutant LUAD tumors should be considered as a distinct subgroup with practical applications in the prognosis and follow-up of LUAD patients.