Yttria stabilized zirconia electrolytes were sintered with addition of iron oxide or chromium oxide. The phase composition of the composites, sintering properties and DC and AC electrical properties are evaluated and compared with available data. Results show, that after sintering there is only single-phase material found in the XRD patterns. Iron can be considered as a sintering promoter while chromium decreases the apparently sintering process, Addition of either oxide decreases total electrical conductivity in comparison to pure samples. Based on impedance spectra it can be concluded that chromium mainly influences electrical conductivity of grain boundary, while iron influences electrical conductivity of both grain and grain boundary, with a solubility limit at grain boundaries estimated at about 2 mol% Fe. (C) 2009 Elsevier B.V. All rights reserved.