Nodule bacteria in symbiotic communities with legumes allow a significant uptake of biologically fixed nitrogen into the soil. The selection of strains that are resistant to stressful soil conditions is of great importance. Selection of highly efficient strains of nodule bacteria (rhizobia) for successful pre-sowing bacterization of legume seed is especially important today, when we are increasingly faced with extreme weather conditions. The aim of this study was to determine the phenotypic characteristics of strains of nodule bacteria isolated from soybean nodules under conditions that are beyond the optimal values for their growth. Soil samples for strain isolation were collected from Koprivnica-Križevci, Bjelovar- Bilogora and Vukovar-Srijem counties. The ability of strains to grow was tested at different pH values, temperatures, salt concentrations and carbohydrate sources. Antibiotic susceptibility was tested as well. In order to determine the biochemical status of each individual isolate, three biochemical tests (oxidase, urease and catalase) were performed, and the morphological characteristics of the isolates were investigated. It was found that most indigenous strains of rhizobia from this study in vitro showed significant resistance to testing conditions, but they also differ significantly from each other in certain properties. Isolates K2 and K3 from Koprivnica-Križevci county showed the highest tolerance to elevated salt concentrations. From tested antibiotics, ampicillin showed to have the weakest effect on the selected isolates, while the isolates were most sensitive to streptomycin. The obtained results indicate the importance of selection of autochthonous strains of rhizobia.