The authors report on the assembly and electrical properties of ultralong copper oxide (CuO) nanofibers prepared by electrospinning method. The prepared CuO nanofibers were polycrystalline, with diameter of similar to 60 nm and length over 100 mu m. By a specially designed fiber collector, single CuO nanofiber field-effect transistor (FET) was assembled directly. Electrical transport measurement was conducted on the nanowire FET device, showing that CuO nanofibers are intrinsic p-type semiconductor. Electrospinning is thus proposed as a simple and low-cost method of fabricating one-dimensional semiconductive ceramic FETs. (c) 2006 American Institute of Physics.