A comparison of methods to create Ohmic contacts to semiconductor nanowires (NWs) and carbon nanotubes (CNTs) is presented. A Ni/Au lift-off metallization was used to contact GaN and In2O3 NWs and CNTs using electron-beam (e-beam) or optical lithography. In order to render the metal-semiconductor contacts Ohmic, e-beam-processed devices are found to require a postfabrication, high-temperature anneal, whereas the use of an oxygen plasma prior to metallization is found to be crucial for devices defined by optical lithography. (c) 2006 American Vacuum Society.