An anhydride/epoxy system is modified by the introduction of thermoplastic microparticles (ORGASOL(R)). The influence of the presence of polyamide (PA) particles is evaluated on the reactivity of the epoxy/anhydride system below the melting temperature of the thermoplastic. Networks containing various amounts of polyamide are prepared using a cure schedule in order to keep the PA particles below their melting point. Both thermomechanical and mechanical behaviours (glass transition temperature, elastic, plastic and fracture properties) are studied and discussed as a function of the polyamide nature, the particle content and the adhesion between the particles and the matrix.