The invention relates to a curing agent for epoxy resins which is an aqueous dispersion of a multifunctional amine AC having more than one primary amino group per molecule, and at least one moiety per molecule derived from the reaction of a compound C containing at least one reactive group which is preferably an epoxide group, with a molecule having at least one blocked primary amino group and at least one group which is reactive towards the at least one reactive group of compound C, which is selected from the group consisting of secondary amino groups >NH, of hydroxyl groups —OH, of mercaptan groups —SH, of amide groups —CO—NHR, where R can be hydrogen or an alkyl group having from one to twelve carbon atoms, of hydroxyester groups, and of acid groups, particularly of carboxyl groups —COOH, sulphonic acid groups —SO3H, and phosphonic acid groups —PO3H2, and preferably, also moieties which are compatible with an epoxy resin, as well as a process for its preparation, and a method of use thereof.