Dye-Sensitized Solar Cells (DSCs) using photoelectrode films fabricated using TiO2 and ZnO nanopowders were investigated. Films having different thicknesses were produced by an electrophoretic deposition technique (EPD) and sensitized using different concentrations of a N719 dye solution. Adsorption isotherms for this dye were obtained and showed different behaviors depending upon whether the adsorbent was TiO2 or ZnO. The photo-electrochemical performance of these DSC's was measured. Cell performance depended on the thickness of films, concentration of dye solution used, and the film structure. The optimal depositional conditions for TiO2 and ZnO were determined. DSCs were prepared using these optimal photoelectrodes. These DSC's were further characterized by linear sweep voltammetry (LSV) at variable wavelengths and by using electrochemical impedance spectroscopy (EIS) in order to obtain the incident photon to current conversion efficiency (IPCE) and the interfacial resistances of the cells, respectively. The performance of DSC containing TiO2 was superior to that of one fabricated using ZnO nanopowders. Lastly, the advantages of DSC's fabricated with TiO2 are discussed. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.070111jes] All rights reserved.