Yttria-stabilised zirconia (YSZ) electrolyte films for solid oxide fuel cell (SOFC) applications were prepared by reactive DC sputtering. The films of 3-9 mum in thickness were deposited onto NiO/YSZ composite anodes. The conductivity of the electrolyte films was determined by impedance spectroscopy. The measured conductivity was low compared to the conductivity of the thick YSZ substrates or bulk material previously reported. The low conductivity of the thin films is explained as an artefact of the contacting electrodes during measurement and not of the deposited films themselves. An estimation of the influence of the contacting electrodes in fuel cell operation on the conductivity of the solid electrolyte is made. (C) 2003 Elsevier B.V. All rights reserved.