This work reports the preparation and structural and electrical characterizations of composites consisting of ethylene-propylene-norbornene, polypropylene, and carbon black (CB) blends, comparing the data obtained from crosslinked and noncrosslinked samples. Structural analysis provided evidence of the reinforcing effect of CB on the properties when present in the initial system, as well as of the excellent conducting properties of CB composites. This, together with their mechanical properties and their extraordinary processing ease, makes them suited as bipolar plates in fuel cells based on polymeric electrolyte.