Nanosized PrBaCo2O5+ë (BCO) particles were prepared by means of a bead milling and deposited on porous backbone of Bi0.5Sr0.5FeO3-ë (BSF55). PBCO was pulverized into very fine particles with crystallite size of 3.0 nm by bead milling. The electrode resistance with nano-PBCO loading decreased with increasing the loading amount of PBCO at temperatures below 550°C implying that nano-PBCO contributed to the acceleration of both electronic conduction and oxygen reduction reaction. Especially, nano-PBCO coated BSF55 with 23.3 mass% of PBCO showed 4.34 ê'cm2 at 500øC. In addition, nano-PBCO loaded BSF55 electrodes showed the lowest electrode resistance compared to normal BSF55 cathode and composite cathode with PBCO (7:3 volume ratio) at temperatures below 600°C.