A new composite consisting of epoxy resin and elastomeric nanoparticles with high, toughness and high heat-distortion temperature is prepared. The size of the nanoparticles used was less than 90 nm. The excellent properties of the composite seem to be due to stronger interactions between the carboxyl groups of the nanoparticles and the epoxy,groups of the resin, and to enhanced hydrogen bonding between the nitrile groups of the rubber and the hydroxyl groups of the resin.