The involvement of different quercetins [quercetin-3-O-rhamnoside (quercitrin), quercetin-3-D-galactoside (hyperoside) and rutin] and catechins (catechin, catechol) in the rooting process of leafy cuttings was studied in two hybrid chestnut (Castanea crenata × Castanea sativa) clones, Maraval and Marsol. Both clones differed strongly in rooting results. The Maraval clone cuttings, which had a high rooting rate, contained, on average, higher amounts of all quercetins in different plant parts (leaves and basal cuttings) than the Marsol clone, which had a low rooting rate. There was a highly significant correlation between the quercetin contents of the cutting leaves and the rooting process (number of main roots). The catecechin contents of the cutting leaves did not show any correlation with the rooting process.