We report studies on the effect of UV/ozone cleaning on n-type GaN nanowires prior to Ti/Al/Pt/Au ohmic contact deposition and the effect of annealing temperature on the total resistance of the contacted nanowires. The UV/ozone cleaning for periods of 1-5 min reduced surface carbon and oxygen contamination, as determined by Auger electron spectroscopy measurements and led to a specific contact resistivity of 1.8 x 10(-2) Omega cm(2) after annealing in the range 700-800 degrees C. After subtraction of this contact resistivity from the total resistance of the nanowires, it was found that the ozone treatment reduced the apparent resistivity from 71 to similar to 0.7 Omega cm. These results show the importance of surface cleaning in extracting the transport properties of GaN nanowires. (c) 2006 The Electrochemical Society.