Metal-semiconductor Au-ZnO and Pt-ZnO films were prepared for enhancing ZnO photocatalytic activity. To increase the photocatalytic area in a metal-semiconductor material system, we introduce an efficient method where the metal and semiconductor are codeposited by an electrochemical method. The photocatalytic activity of Au-ZnO shows a better performance than that of Pt-ZnO determined by the degradation ability of methelene blue. There is an optimized Au concentration (similar to 2%) in Au-ZnO film for its best photocatalytic activity. (C) 2008 The Electrochemical Society. [DOI: 10.1149/1.2990719] All rights reserved.