Electrical conductivity relaxation (ECR) experiments were carried out on La0.6Sr0.4Fe0.8Co0.2O3-delta '(LSFCO)' in the temperature range of 840 to 910 C and in the oxygen partial pressure range of 0.01 to 0.05 atm. The effects of annealing at 900 degreesC on the oxygen transport properties were investigated for individual samples. The values of D-O(2) = (D) over tilde (O)/Gamma(O) and k(ex)=k(chem)/Gamma(O) agree well with the result from isotope-exchange depth profile (IEDP) experiments. (C) 2003 Elsevier Science B.V All rights reserved.