Preservation of soil microbial diversity and utilization of beneficial microbiological processes is becoming crucial in new concepts of agricultural development. Legumes are grown primarily for their seeds and are essential in the human diet due to their high protein content. Their role as forage crops as well as green manure is also very important. The symbiosis of rhizobia and legumes is of great significance for agroecosystems. Rhizobia are a group of soil bacteria that nodulate legumes and establish a symbiotic relationship in which fixation of atmospheric nitrogen takes place. In order to utilize symbiotic nitrogen fixation, inoculation of legume seeds is performed thus reducing the need for the application of mineral fertilizers. More recently, new species of rhizobia have been discovered which has led to significant changes in taxonomy and new possibilities for their application. For the success of inoculation, it is necessary to choose strains that must be highly efficient, compatible with certain varieties of legumes, adapted to adverse environmental conditions and competitive with indigenous strains. Therefore, the importance of rhizobial selection is emphasized with the aim of choosing the highest quality strain for inoculation and cultivation of a specific legume in order to increase yield and product quality and allow greater use of nitrogen fixation process.