The effect of inoculation of Rhizobium leguminosarum, Azotobacter chrooccoccum and exogenous phytohormones on pro - and antioxidant activity of the peroxidase enzyme system in the cells of seedling roots ofpea was studied. It is shown that Rhizobium increases the IAA-oxidase function ofperoxidase in soluble and bound to cell walls fractions of the enzyme, which is obviously associated with the regulation of the initial stages of infection. The effect of Azotobacter on the oxidase and peroxidase activity of the enzyme has the same, but more pronounced, orientation with the action of exogenously added to Rhizobium IAA. Joint inoculation of Rhizobium with Azotobacter has a positive effect on the growth of seedlings and causes modulation in the ratio ofpro - and antioxidant functions ofperoxidase in different fractions of the enzyme in comparison with only Rhizobium inoculation.