The electronic conductivity of La0.4Sr0.6FeO3-delta is studied in the oxygen partial pressure range 10(-5)less than or equal topO(2)/atmless than or equal to1 temperatures 100less than or equal toT/degreesCless than or equal to900. The oxygen partial pressure dependence of the electronic conductivity in the pO(2) range under investigation shows a predominantly p-type character. Combination of the pO(2) dependences of the oxygen nonstoichiometry delta and the electronic conductivity a at constant temperatures 600less than or equal toT/degreesCless than or equal to900 indicates a significant decrease of sigma with increasing delta. Concentrations of electronic defects are calculated from experimental data of the oxygen nonstoichiometry via a point defect model and applied to modelling of sigma as a function of delta. The mobility of holes is estimated from the electronic conductivity and the calculated charge carrier concentrations as a function of oxygen nonstoichiometry. At constant pO(2), the electronic conductivity is thermally activated at T<300 degreesC, but decreases with further increase of temperature due to desorption of oxygen from the lattice. This effect is especially pronounced in the intermediate pO(2) range 10(-4)less than or equal topO(2)/atmless than or equal to10(-2) where significant oxygen deficit occurs. The temperature dependence of the electronic conductivity of La0.4Sr0.6FeO3-delta was combined with results of the temperature dependence of the oxygen nonstoichiometry. Thus, activation energies for electronic conduction at constant oxygen content were obtained for the high temperature region (T>300 degreesC) which are in agreement with isobaric activation enemies of the electronic conductivity at low temperatures (T<300 degreesC) (C) 2004 Elsevier B.V. All rights reserved.