Legume seed inoculation prior to sowing is a well-known practice in agriculture. Nitrogen fixation, due to the symbiotic relationship between legumes and rhizobia, improves the productivity of legumes. Rhizobia strain specificity can be observed very often, leading to differences in the total protein content. In this study two faba bean cultivars (‘Karmazyn’ and ‘Bartek’) and five pea cultivars (‘Retrija’, ‘Zaiga’, ‘Lāsma’, ‘Vitra’ and ‘Bartek’) were tested using various rhizobia strains. In addition, strain effectivity was observed in four different soil types. Overall, the protein content increase was observed after seed inoculation with