Photoconduction studies have been carried out with single crystal GaN nanowires. The nanowire transistors exhibited a substantial increase in conductance upon UV light exposure. Besides the selectivity to different light wavelengths, extremely short response and recovery time have also been obtained, as well as the great reversibility of the nanowire between the high and low conductivity states. In addition, a polarization anisotropy effect was demonstrated and studied for GaN nanowires working as polarized UV detectors. The nanowire conductance varied periodically with the polarization angle of the incident light (theta), which can be well fitted into a function of cos(2)theta. (C) 2004 Elsevier B.V. All rights reserved.