Ethylene-propylene-diene terpolymer, EPDM structure foams of different apparent densities was compounded by using different concentration of foaming agent, azodicarboamide, ADC/K. The electrical conductivity was measured under different compression strains; 0%, 10%, 30%, 40%, 50% and 60%. The stress relaxation at different compressive stresses was also measured. The change of conductivity under the effect of compression strains was explained by the aid of calculated carbon black shape factor. The effect of the foam structure on the electrical properties (dc and ac) of the reinforced carbon black- EPDM system was studied.