For agricultural production symbiosis of nodule bacteria and legumes is very important. Therefore, it is important to choose the highly effective strains that are resistant to various unfavorable conditions in the soil. The selection of highly efficient strains of rhizobia is essential to the success of legume seed inoculation because today we are increasingly faced with extreme weather phenomena due to the climate change. The aim of this thesis is to determine the phenotypic characteristic of nodule bacteria strains isolated from soybean nodules from a flooded area of Županja in Posavina in conditions that are beyond the optimum value for their growth. The growth of the strains was studyed at different pH values, temperatures, concentrations of salts and heavy metals, and carbohydrate sources. It was found that the studied isolates of nodule bacteria can grow at temerature of 37 C which is higher than their optimum temperature (26 – 30 C). Most of the tested nodule bacteria isolates, than normally have the best growth in the neutral media, tolerate alkaline and acidic environment. The study showed that isolates do not tolerate the increased concentration of salt and do not grow on the substrates with copper. They showed good growth in other sources of carbohydrates apart from glucose, and on the surfaces with zinc and manganese, while on the surfaces that contain cadmium they showed a partial growth.