In this paper, electrical and electrochemical properties of La(0.6)Sr(0.4)Co(0.2)Fe(0.8)O(3-delta) (LSCF) cathode have been studied. The sample is prepared by solid-state reaction method. The results of the X-ray diffraction have been analyzed by FullProf software and it has been found that LSCF phase has been formed. Resistance of the sample versus temperature in air atmosphere has been measured and the results show that, it decreases by increasing temperature. Activation energy for electrical conductivity has been calculated by fitting the Arrhenius plot with experimental data. Also, resistance of sample has been measured at the different temperature ranges and in the presence of Oxygen/Argon atmosphere. Using electrical relaxation technique and some approximations, ionic diffusion coefficient and activation energy for ionic conductivity have been calculated. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.