3-mol% Y2O3 and 0.3 to 3-mol % Cr2O3 co-doped ZrO2 nanopowders were synthesized using co-precipitation technique and investigated by terms of X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. Structural analysis shows no significant impact of chromium on powders structure except of presence of small amount of m-phase. Surface analysis reveals segregation of yttrium and chromium atoms to the surface along with surface enrichment by oxygen that can be attributed to residual water. Chromium surface atoms present in three oxidation states with catalytically active Cr2+ sites possibly controlling m-phase appearance through lattice distortion. (C) 2010 Elsevier B.V. All rights reserved.