The photoluminescence properties of polyaniline modified ZnO nanostructures electrodeposited on ITO glass have been investigated. The great enhancement of the peak intensity ratio of ultraviolet to visible emission was observed after the polyaniline modification on the ZnO nanostructured films. Such enhancement can be ascribed to the passivation effect caused by the polyaniline surface modification. This simple modification method provides a chance for various ZnO nanostructures to improve their ultraviolet emission property for the optoelectronic applications. (C) 2007 Elsevier B.V. All rights reserved.