The fabrication and characteristics of laterally grown ZnO nanowire/p-GaN heterojunction light emitting diodes are reported. The ZnO nanowires were grown using a direct single-step method on a prepared p-GaN patterned substrate. The rectifying current-voltage characteristics indicate that a p-n junction was formed with a heterostructure of n-ZnO nanowire/p-GaN. The room-temperature electroluminescent emission peak at 430 nm was attributed to the band offset at the interface between n-ZnO nanowire and p-GaN and defect-related emission from GaN. (C) 2010 The Electrochemical Society. [DOI:10.1149/1.3459933] All rights reserved.