The Rilsan PA11 prepolymer was evaluated as a curing agent of a diepoxy prepolymer (DGEBA). The miscibility, the glass transition temperature, and the melting of the blend were studied as a function of time at 200 degrees C. A gelation phenomenon was evidenced by dynamic mechanical analysis and the gel time was determined at 200 degrees C. The participation of amide groups to the reaction process at this temperature was confirmed by the study of the PA12 Orgasol(R)/DGEBA system and a reaction mechanism was elucidated by the study of a model system composed of ethylacetamide/phenyl glycidyl ether. The mechanical properties of DGEBA/Rilsan networks cured 7 h at 200 degrees C were evaluated and indicate very high Young's modulus and critical stress intensity factor.