Ba1-xLaxSc1-yZryO3-delta with perovskite-related structure was synthesized by dopes of La and Zr to Ba-site and Sc-site of Ba2Sc2O5, respectively. The lattice parameters were refined by the Rietveld analysis with space group Pm3m. The total electrical conductivities of Ba1-xLaxSc1-yZryO3-delta measured by DC four-probe method were found to be about 10(-2) S(.)cm(-1) at 1000 degrees C in air and contributed by oxide ion, proton, and hole. The oxide ion transport number of Ba1-xLaxSc1-yZryO3-delta determined by ion blocking method increased with decreasing temperature. (c) 2005 Elsevier B.V All rights reserved.