Polythiols prepared by the reaction of hydrogen sulfide or organic dithiols with polyglycidyl substituted amines have been found to be outstanding curing agents for epoxy resins. Epoxy resins cured with these polythiols are characterized by not only improved gel times, but also improved cure rates, better heat resistance and greater resistance to absorption of water.A useful polythiol is the reaction product of N,N,N',N'-tetraglycidyl-m-xylylenediamine with hydrogen sulfide.