Ethylene-propylene-diene terpolymer rubberlnatural rubber blends (EPDM/NR) in different proportions (100 : 0, 75 : 25, 50 : 50, 25 : 75, and 0 : 100) reinforced with 20 phr semireinforcing furnace carbon black have been studied. The permittivity ε' and dielectric loss ε″ for these samples were determined in the frequency range 102–107Hz. Also, their physico-mechanical properties were investigated.