The oxygen ion and electron transport in SrFe1-xScxO3-delta (x=0.1-0.3) system at 700-950 degrees C were studied analyzing the total conductivity dependencies on the oxygen partial pressure, pO(2). The conductivity measurements were performed both under reducing conditions (10(-19)<= pO(2)<= 10(-8) atm) comprising the electron-hole equilibrium point, and in oxidizing atmospheres (10(-5)<= pO(2)<= 0.5 atm) which are characterized by extensive variations of the oxygen content studied by coulometric titration technique. The incorporation of 10% Sc3+ cations into the iron sublattice suppresses transition of the cubic perovskite phase into vacancy-ordered brownmillerite, thus improving ion conduction at temperatures below 850 degrees C. When scandium content increases, the ion conductivity becomes considerably lower. The hole mobility is thermally-activated and varies in the range of 0.001 to 0.05 cm(2) V-1 s(-1), increasing with oxygen concentration and decreasing on Sc doping. (c) 2006 Elsevier B.V. All rights reserved.