Bacterial endophytes were isolated from nodules of pea and faba bean. The strains were identified and characterized for plant beneficial activities (phosphate solubilisation, synthesis of indole acetic acid and siderophores) and salt tolerance. Based on these data, four strains of Rahnella aquatilis and three strains of Serratia plymuthica were considered as potential Plant Growth-Promoting Bacteria, able to support plant development in saline soils. In order to shed light on the mechanisms underlying salt tolerance, the proteome of the two most performant strains (Ra4 and Sp2) grown in presence or not of salt was characterized. The amount of protein expressed by the endophytes was higher in presence of salt. The modulated proteome was composed by 302 (100 up-regulated, 202 down-regulated) and by 323 (206 up-regulated, 117 down-regulated) in Ra4 and Sp2, respectively. Overall, proteins involved in abiotic stress responses were up-regulated, while those involved in metabolism and flagellum structure were down-regulated. The main up-regulated proteins in Sp2 was thiol:disulfide interchange protein DsbA, required for the sulphur binding formation in periplasmic proteins, while in Ra4 corresponded to the soluble fraction of ABC transporters, having a role in compatible solute uptake. Our results demonstrated a conserved response to salt stress in two taxonomically correlated species.