Epoxy resins based on 4,4’-dihydroxydiphenylsulfone (DGEBS) and diglycidyl ether of bisphenol A (DGEBA) were prepared by alkaline condensation of 4,4’-dihydroxydiphenylsulfone (bisphenol S) with epichlorohydrin and by recrystallization of liquid, commercial bisphenol A-type epoxy resin, respectively. Curing kinetics of the two epoxy compounds with 4,4’-diaminodiphenylmethane (DDM) and with 4,4’-diaminodiphenylsulfone (DDS) as well as T-g values of the cured materials were determined by the DSC method. It was found that the -SO2- group both in the epoxy resin and in the hardener increases T-g values of the cured materials. DGEBS reacts with the used hardeners faster than does DGEBA and the curing reaction of DGEBS begins at lower temperature than does the curing reaction of DGEBA when the same amine is used.