Synthesis and properties of epoxyfumarate and epoxymaleate resins obtained by the addition of acidic benzyl maleate to the commercially available epoxy resin are presented. The resins were synthesized in one- and two-step procedures. In the two-step procedure, acidic benzyl maleate was synthesized separately and then used for the addition reaction with epoxy resin, Epidian 5. In the one-step procedure, acidic ester was formed during the synthesis process. Properties of the resins in a noncrosslinked state, during curing, and after crosslinking were compared.