A series of polymer electrolytes, PEO(9)Zn(1-x)Cu(x)(CF3SO3)(2), where PEO is poly(ethylene oxide) and x varied between 0.0 and 1.0, was investigated by differential scanning calorimetry, complex impedance analysis and electron paramagnetic resonance (EPR) spectroscopy. The mixed cation complexes show no evidence of a crystalline phase, and a prominent conductivity maximum occurs at the 50/50 Zn/Cu composition. The conductivity maximum does not correspond to the sample with the lowest glass transition temperature, nor is it correlated with local Cu2+ motions probed by EPR. These results, along with preliminary transference number determinations, suggest that the CF3SO3- ions are the dominant charge carriers.