Alfalfa (Medicago sativa) is a ubiquitous forage legume crop, responsible for the nutrition of many of the world's livestock animals. Unfortunately, alfalfa suffers from insufficient levels of salinity tolerance in many semi-arid regions around the world, including western Canada. To attempt to find ways to mitigate salinity stress in alfalfa, this study combined conventional breeding techniques with inoculation by mutualistic soil bacteria. Three alfalfa generations sequentially selected for improved salt tolerance were inoculated with either highly salt-tolerant (H. maura), moderately-tolerant (Ensifer meliloti) bacteria, or a 60 kg/ha nitrogen amendment in either non- (0 dS/m), moderate-(8 dS/m), or highly (16 dS/m) saline soil in the greenhouse. Plants were assessed for success in saline conditions through root/shoot biomass measurements, shoot height, chlorophyll content, number of stems, and root and shoot osmoprotectant concentrations (proline, glycine betaine, and trehalose). Results showed that rhizobium was the most beneficial bacteria to alfalfa under moderately saline conditions, and that generation 2 appeared to be the most salt-adapted alfalfa population. Additionally, nitrogen amendments appeared to provide benefits to biomass and osmoprotectant production. The salt-tolerant bacteria H. maura failed to provide any benefits to alfalfa growth, suggesting that reported benefits from the previous studies may be genotype/location specific. The improved performance of generation 2 relative to generation 3 may suggest the onset of an inbreeding depression, to which alfalfa (being an outcrossing species) is susceptible. These findings suggest nitrogen may be an important nutrient for alfalfa under moderately salt-stressed conditions, and that intense selection may be less effective than moderate selection intensity for the improvement of salinity tolerance.