Electrical and oxygen transport properties of SrFeCo0.5Ox oxide were investigated at elevated temperatures. The electrical conductivity was found in the order of 20-10 S/cm in the temperature range of 1100-600 degreesC. An abnormal region was observed at temperatures around 900 degreesC in which electrical conductivity increased with decreasing temperature, which may be related to the undergoing of phase transformation. An oxygen permeation flux of 159 x 10(-8) mol/cm(2).s was measured in an air/helium gradient at 900 degreesC. The acid treatment on the sintered oxide resulted in a considerable improvement of the oxygen permeability, indicating that the surface oxygen exchange limits the overall oxygen permeation process. (C) 2000 Elsevier Science B.V. All rights reserved.