The method of obtaining of epoxy-oligoester compositions based on ED-20 dyano epoxy resin in the presence of modified ED-20P epoxy resin was developed. The influence of amount of epoxy components and unsaturated MGPh-9 oligoester on structuring process of epoxy-oligoester blends was studied. The heating of such blends causes complete decomposition of labile peroxide groups and also subsequent polymerization of unsaturated oligoesters which, in the presence of ED-20P resin is included to the crosslinked structure of blend providing the derivation of epoxy-oligoesters with improved physical, mechanical and chemical properties.