X-Ray photoelectron spectroscopy (XPS) has been used to study the valence bands of yttria-stabilized zirconia (YSZ) and YSZ-alumina composites. XPS valence bands are sensitive to near-surface phase transformations in these ceramics and have been used to monitor phase changes due to wear and surface modifications. In the case of surfaces with mixed phases, XPS valence bands have been used in a semiquantitative way to characterize the constituent phases. In general, the paper illustrates the utility of XPS valence bands in studying complex ceramic surfaces tailored for specific application.