Abstract. The study is aimed at analyzing the oxidoreductase activity of seeds and seedlings of soybean infected with a fungal infection of Septoria glycines Hemmi. Research Methods. The object of the study was seeds collected from soybean plants (Glycine max (L.) Merr) of the Lydia cultivar grown on meadow chernozem-like soil of the experimental field of the All-Russian Research Institute of Soybean in s. Garden of the Amur Region in 2019. The content of malondialdehyde was determined using thiobarbituric acid. The activity of superoxide dismutase and catalase was determined spectrophotometrically, and the activity of peroxidase and polyphenol oxidase was determined by the colorimetric method. Electrophoretic spectra of the studied enzymes were detected by electrophoresis on columns of a 7.5% polyacrylamide gel. Detection on a gel of zones with enzymatic activity was carried out by appropriate histochemical methods. Results. As a result of studies, it was found that on the 10th day the infection of the seedlings was 8.75 %. In this case, under the influence of Septoria glycines Hemmi, a slowdown in growth processes was observed, the level of malondialdehyde increased, which indicates an increase in oxidative processes. The length of seedlings infected with septoria was 2.7 % less compared to uninfected ones; the mass of infected seedlings decreased by 0.15 g. When soybean infection with Septoria was detected, soybean seeds and seedlings responded, expressed in a change in the specific activity of the studied enzymes and their rearrangement multiple forms. Reduction of oxidative stress in the seeds occurred due to an increase in the activity of superoxide dismutase, peroxidase and polyphenol oxidase, for seedlings – due to an increase in the activity of peroxidase only. Scientific novelty. It has been established that superoxide dismutase in soybean seeds has a high responsiveness to the pathogen. This is expressed in increased specific activity and significant polymorphism of the enzyme, which allows it to be used as a molecular marker for increasing soy resistance to the pathogen.