Relevance. Rhodiola rosea L. is a perennial herbaceous plant from the Crassulaceae family. The roots and rhizomes of R. rosea contain a range of biologically active compounds. This species is included in the State Pharmacopoeia of the Russian Federation. Medicinal preparations derived from them are widely used as adaptogens, general tonic and anti-stress agents. While the roots have been extensively studied, less attention has been given to the biologically active compounds found in the leaves of R. rosea. An introduced population of R. rosea grows on the territory of the botanical garden of medicinal plants of the All-Russian scientific research Institute of medicinal and aromatic plants (VILAR). The possibility of cultivating this species in the conditions of the Moscow region is being studied.Material and Methodology. The objective of this study was to investigate the composition of phenolic compounds in R. rosea leaves from VILAR biocollection using ultra-efficient liquid chromatography combined with mass spectrometry. Extraction was carried out with 80% acetone. An ultra-high performance liquid chromatographic system with a photodiode array detector and mass spectrometer was used for the analysis of phenolic compounds. Identification was carried out using UV- and mass spectrometry data.Results. As a result of UPLC-DD-MS analysis, peaks of 20 phenolic compounds were detected in R. rosea leaves, of which 19 compounds were tentatively identified. The leaf extract contained eight phenolic compounds from the group of galloyl-glucoses (three isomers of monogalloyl-glucose, trigalloyl-glucose, two isomers of tetragalloyl-glucose, two isomers of pentagalloyl-glucose), two gallotannins (isomers of hexagalloyl-glucose), five flavonoids (four herbacetin derivatives and one gossypetin), phenolic acids (caffeoyl-malic and ferulic acids), arbutin and esculetin. It has been shown that the biologically active substances of R. rosea provide prospects for the use of leaves as raw materials for the development of herbal preparations with anti-inflammatory, antiviral and antitumor effects.