Grapevine leaves are a major by-product of viticulture practices derived from the leaf-removal from the fruit cluster zone in all vine growing regions. These leaves can be a valuable source of antioxidants to be used in pharmaceuticals or other health-related products. In this study, the leaves of grapevine cultivars were analysed by ultra-high performance liquid chromatograph-diode array detector () for the total polyphenols (TPC) and resveratrol affected by cultivar, leaf-removal time and viticultural practice. The effect of cultivar varied yearly, European grapevine cv. &lsquo grown under the polytunnel had decreased TPC in leaves. In conclusion, cultivar selection, viticultural practice and leaf-removal time contribute significantly to the accumulation of total polyphenols and resveratrol. Results of this study will contribute to better utilization of biomass produced in the vineyards, help to decrease the negative environmental impacts, and provide an overview on various factors affecting the biochemical constituents, especially in leaves. 1) were higher in leaves of interspecific hybrid cvs. &lsquo had increased TPC and resveratrol in comparison to &lsquo 1) and resveratrol (1.061 mg 100 g&minus during full fruit ripeness. Cv. &lsquo in 2018. TPC (1213&ndash Hasansky Sladky&rsquo 1841 mg 100 g&minus in 2017, but &lsquo Boskoop&rsquo s Glory&rsquo Solaris&rsquo Regent&rsquo Rondo&rsquo Zilga&rsquo and &lsquo , &lsquo