Bacteria associated with leguminous species of the genus Astragalus (specifically Astragalus armatus) were isolated. The isolates were characterized through a phenotypic study, which included physiological, nutritional, and biochemical tests.A core sampling test was conducted under bacteriologically controlled conditions, following Vincent's (1970) technique. Subsequently, a total protein profile was obtained under denaturing conditions using the SDS-PAGE electrophoresis technique, as described by Laemmli ) 1970 ( . The results indicate that our isolates exhibit characteristics specific to rhizobia, in the presence of reference strains R. leguminosarum, Mesorhizobium ciceri, and R. sullae. In order to finalize this work, a molecular characterization was carried out. The analysis of total protein profiles under denaturing conditions using SDS-PAGE, the profiles exhibit polymorphism between the reference strains and the isolates; however, some profiles of the isolates (Ast 7, 8, 9, and 12) match that of Mesorhizobium ciceri. In the taxonomic aspect, particularly molecular identification, ARDRA profiles of DNA digested with the endonuclease CofI, and sequencing of the 16S rRNA gene using the Sanger technique, the NCBI blast sequence reveals the strains belonging to the γ-Proteobacteriaceae family and the families Brucellaceae. Where lead to the identification of a bacterial genus, Ochrobactrum sp., a genus recently studied and recognized as nodulating legumes.