The stems of Rubus idaeus L., a by-product of the fruit-food industry, are known sources of bioactive compounds. The main objective of this study was to investigate the composition of the polyphenolic compounds in R. idaeus stems. 7 cultivated raspberry varieties, 13 garden samples, including five well-known raspberry varieties and 13 wild raspberry samples from different locations in Estonia were analyzed. The HPLC-MS method detected 62 substances, of which 42 were identified, 12 were tentatively identified, and 8 compounds remained unknown. Protocatechuic acid pentoside was dominant in most varieties and in all garden and wild raspberry samples. Dihydroxybenzoic acid hexoside 1, p-coumaroyl quinic acid 1, quercetin 4’-glucuronide and p-coumaric acid glycoside were found in significant quantities. Correlations between the contents of individual compounds have been established. When studying the dynamics of polyphenolic compounds accumulation on the example of the GR1 sample during the year, it was found that the largest amount of them in raspberry stems accumulates in April, slightly less in January and October. Investigating the dependence of the accumulation of polyphenols on the parts of the stem, it was found that the upper parts have the highest phenolics content. Therefore, it is recommended to harvest approximately the upper third of the stem.