Syntheses of epoxy-based divinyl ester resin and its modification with toluene diisocyanate (TDI) are presented. The resin was obtained from commercially available epoxy resin Epidian 5 and methacrylic acid during graduated heating. Three different resin solutions were obtained by adding 45, 50, and 55% of styrene; then, each solution was modified with TDI at room temperature. Properties of the resins before and after modification were studied.