The aim of these studies was to assess various isolates of symbiotic bacteria of lupine and soybean with respect to their effects on nodulation and seed yields of the crops. Strains of Bradyrhizobium sp. (Lupinus) and Bradyrhizobium japonicum, belonging to the collection of these bacteria at Dept. of Agricultural Microbiology IUNG-PIB Pulawy, were used for inoculation of lupine seeds (cv. Mister and Baron) and soybean seeds (cv. Aldana and Nowiko). In pot experiments (Mitscherlich pots containing 7 kg of soil) none of the tested strain of lupine rhizobia significantly increased lupine seed yields though some of these strains improved nodulation of lupine plants. All B. japonicum strains – soybean symbionts – markedly stimulated nodulation and significantly improved seed yields of both soybean cultivars.