A dense film of YSZ was coated by electrophoretic deposition (EPD) method on graphite coated NiO-YSZ composite by acetone-ethanol media that were associated with different amount of deionized water. Addition of deionized water into the suspensions influenced significantly not only on the weight of deposition but also on the quality of the deposited surface. A maximum weight of deposition was obtained by addition 4% of water, where the most uniform surface was achieved. Zeta potential and weight of deposition had similar trends of variation. The sintered films were also show the homogeneous surface in this optimum percentage of water. Microstructures of electrophoretically deposited YSZ films were investigated by Scanning Electron Microscope (SEM) for green and sintered ones. In addition, the most homogeneous film had the minimum electrochemical impedance after consequence sintering. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.