Effect of two plant growth stimulators: bactozol (drug of bacterial origin) and D1 (synthetic analog of phytohormones) on metabolism of pea rhizobia (Rhizobium leguminosarum bv. viciae 2636) and efficiency of their symbiosis with pea plants have been studied. The D1 drug in concentration 0.1% suppressed growth of bacteria. However, bactozol stimulating action on pea rhizobia growth in a pure culture and synthesis of extracellular carbohydrates by them have been established. The trial of three concentrations (0.1%, 0.01%, 0.001%) has shown that bactozol effect has dose-dependent character. The highest effect of stimulation is achieved at concentration 0.1%. Bactozol decreases partially the repressing influence of the mineral nitrogen on growth of rhizobia and their carbohydrate-synthesizing activity under growth of bacteria against a high nitrogen background (20 mM NO3-). Treatment of pea plants by bactozol (0.1%) increases considerably the efficiency of their symbiosis with pea rhizobia, evoking the growth of the overground and root mass of the plants, quantity of nodules and their nitrogenase activity.