The changes in the composition and content of phenolic compounds in the leaves and inflorescences of Hedysarum alpinum L. and H. flavescens Regel et Schmalh., introduced into the forest-steppe zone of Western Siberia, were studied. Using the example of H. alpinum, the variation in the content of phenolic compounds depending on the year of harvest and on the plant organ (leaves, inflorescences) was investigated. The contents of individual substances (gallic acid, chlorogenic acid, mangiferin, hyperoside, rutin, avicularin, and 17 phenolic components) and of phenolic compounds by groups (hydroxycinnamic acids, hydroxybenzoic acids, xanthones, and flavonols) were determined. Differences in the content of phenolic compounds by groups (in mg/100 g) were found between the two species of the genus Hedysarum L. Specifically, the leaves of H. alpinum accumulated more xanthones and flavonols (up to 4614.9 +/- 63.7 and 1280.0 +/- 6.7, respectively) and the inflorescences, more xanthones (up to 847.9 +/- 29.8) compared to the leaves (2911.6 +/- 79.0 and 976.2 +/- 0.5, respectively) and the inflorescences (76.2 +/- 2.5) of H. flavescens. In the leaves of H. flavescens, compared to the leaves of H. alpinum, the content of hydroxybenzoic acids and hydroxycinnamic acids prevailed. The leaves of the studied species accumulated mostly hydroxycinnamic acids and xanthones, and the inflorescences, mostly flavonols. The contents of hydroxybenzoic acids, xanthones, and flavonols in H. alpinum varied significantly depending on the year of observation.