GaN optoelectronic devices based on nanowires offer potential advantages that merit further investigation for applications in solid-state lighting and displays. Reported is the operation GaN nanowire, light-emitting diodes that are based on a uniform and scalable nanowire process. For light-emitting diodes consisting of approximately 300 nanowire pn homojunctions, operating in parallel, the electroluminescence intensity was found to grow superlinearly with current. For individual nanowire light-emitting diodes the forward and reverse leakage current was<1 pA. The low leakage current of individual light-emitting nanowire diodes indicates that surface effects do not dominate the electrical behaviour of these LEDs.