Filled EPDM materials have been processed and aged by gamma radiation at ambient temperature and at 80 degrees C to study the influence of the fillers presence in the material degradation. The acceleration of the polymer degradation by the ATH fillers, evidenced when irradiation is performed at 25 degrees C, is also effective at 80 degrees C. In addition, in the case of silica-filled EPDM, the creation of strong filler-matrix bonds, already reported for irradiation at 25 degrees C, is also thermally activated; this enables to this material to keep its integrity at high irradiation dose, whereas the irradiated ATH-filled EPDM is so degraded that it flows. Thus, the introduction of fillers in the polymer has an impact on its resistance to irradiation, whatever the temperature at which the irradiation is performed. Moreover, the consequences of the degradation on the evolution of the mechanical properties of the composite are very dependent on the filler nature. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1319-1328, 2010