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Drought adapted tepary bean (Phaseolus acutifolius A. Gray) is a promising resource to cultivate under extreme climatic conditions of the arid-desert regions. However, the production depends on the appropriate supplementation of nitrogen rich-fertilizers. Application of specific halotolerant nitrogen-fixing bacteria associated with P. acutifolius could be an important practice for crop production in salt-affected regions. Twenty-four halotolerant endophytic bacterial colonies were isolated from seeds of different ecotypes of Phaseolus acutifolius cultured in 0, 0.25, 0.5 and 0.75 M NaCI concentrations. The nitrogen fixation ability of the bacterial isolates were screened by acetylene reduction assay. Among 24 bacterial isolates, only one showed high acetylene reduction activity of 6.97 1.1 nmol culture-1 h(-1). The 16S rRNA gene sequencing result revealed that the nitrogen fixing bacteria was closely related to Bacillus amyloliquefaciens (96.2% similarity). The effects of B. amyloliquefaciens, in conjunction with Azospirillum halopraeferens were tested for seed germination and early seed growth promotion of P. acutifolius ecotypes exposed to higher salinity at 0, 0.25, 0.5 M NaCI under in vitro and greenhouse conditions. Results pointed out that inoculation with B. amyloliquefaciens had more stimulating effect on growth parameters of P. acutifolius than well-studied A. halopraeferens strain. A reliable biological method, based on beneficial bacteria, is suggested to maintain the soil fertility or improve sustainable agriculture in arid regions.