White mulberry tree (Morus alba L) is culti-vated throughout Asia and Europe, includ-ing Poland. The leaves and root bark prep-arations from Morus alba have been used in traditional phytomedicine. The objective of the present study was to compare chemical composition and antioxidative activity of aqueous extracts prepared from Polish va-riety of Morus alba leaves at the laboratory (L) and pilot plant scale (PP) conditions. Proximate composition, phenolic acids profile (HPLC/MS), flavonol glicosides (HPLC/MS), polyphenols (Folin-Ciocalteu assay), and the antioxidant activity (ABTS and DPPH assay) of the extracts were de-termined. The main phenolic compounds were identified as gallic, protocatechuic, p-hydroxybenzoic, vanillic, chlorogenic, caffeic, p-coumaric, ferulic, and sinapic acids. Chlorogenic acid was the main phe-nolic constituent of both extracts. The flavonols fraction contained rutin, quercetin 3-β-D-glucoside, and kaempferol 3-β-D- glucopyranoside. Total concentration of phenolic compounds was 7.9 g and 14.4 g gallic acid equivalent/100g extract, and antioxidant activity was 137.1 and 214.1 μMol Trolox equivalent/g dry weight for the PP and L extracts, respectively. We concluded that current pilot plant process is less efficient than laboratory process at the aqueous extraction of bioactive components from Morus alba dried leaves. Potential im-provements may include increasing effica-cy of the extraction, decreasing losses of bioactive components during the process, or both.