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Abstract: PrBaCo2-x Fe x O5+ δ (PBCFx, 0≤ x ≤2.0) is investigated as cathode materials for intermediate temperature solid oxide fuel cells. X-ray diffraction confirms that the material retains double perovskite structure and undergoes structural change from tetragonal to cubic as the Fe doping level reaches to x =0.4. High-temperature X-ray diffraction patterns reveal that all the structures of PBCFx (x =0.0→0.4) are thermodynamically stable upon heating to 900°C. The increased doping of Fe deteriorates the electrical conductivity monotonically, with an exception of a big jump in the conductivity at x =0.4, due to the structural change. Thus, except for the low temperature region of 50–400°C, PBCF0.4 possesses maximum values in the electrical conductivity at temperature range of 500–900°C among all the Fe doping levels in PBCFx. PBCF0.4 used as cathode in the symmetrical cells of PBCFx/Ce0.8Sm0.2O2-γ (SDC) exhibits the lowest cathode polarization resistance: 0.07Ωcm2 and 0.13Ωcm2 at 750°C and 700°C respectively. For anode-supported button cells of PBCFx|SDC|NiO+SDC, the highest power density is also observed for PBCF0.4 with a maximal power density of 446.4 and 346.3mWcm−2 at 700 and 650°C, respectively. We conclude that Fe doping does not increase the conduction properties by itself but improves the electrochemical properties indirectly by changing the structure of PBCFx from tetragonal into cubic. [Copyright &y& Elsevier]