The morphology and physical properties of dicyandiamide (DICY)-cured epoxy resins modified with ion-crosslinked core/shell acrylic particles were studied. The modified epoxy resins displayed excellent adhesion and semi-gelling properties simultaneously. When an epoxy resin derived from ethylene oxide and bisphenol A was used as a reactive diluent in this system, both the adhesion strength and the impact strength increased. This result is attributed to relaxation of the internal stress of the cured epoxy resin as a result of using a flexible epoxy resin.