Equilibrium between ABA biosynthesis and catabolism regulatesABAaccumulation in plants underwater stress. The aim of our work was to explore the dynamics of changes in ABA metabolites as well as other stress-induced phytohormones such as jasmonic acid, indole-3-acetic acid, and their respective metabolites in hop [Humulus lupulus (L.)] plants during drying and to identify among them potential signals involved in drought signalling. We showed that the concentrations of all ABA metabolites (except the concentration of ABA glucosyl ester in leaves) increased in the same manner in leaves and xylem sap approximately at the same level of soil water content when the relative water content of leaves decreased. The predominant metabolites in leaves and xylemsap were phaseic acid and dihydroxyphaseic acid.ABA glucosyl ester was not a source of the increased concentration of ABA in leaves and xylem sap because of its considerably lower concentration compared to ABA.