Abstract: A hardening agent for an aqueous epoxy resin composition comprising a reaction product of (a) at least one polyepoxide compound, (b) at least one polyalkylene polyether polyol and (c) at least one compound selected from the group consisting of aliphatic, cycloaliphatic and heterocyclic polyamine and wherein component (c) additionally may be reacted with (d) an unsaturated compound before or after the reaction with the adduct of components (a) and (b), process for preparing said hardening agent and hardenable film forming coating compositions comprising as essential ingredients said hardening agent, at least one polyfunctional epoxy compound (a) and water.