A ZnO nanofiber field-effect transistor (FET) was assembled by electrospinning. Uniform ZnO nanofibers with a diameter of similar to 70 nm and length over 100 mu m were first synthesized by electrospinning. Using two paralleled electrodes as fiber collectors, we have successfully placed a single ZnO nanofiber on the electrodes, and an FET device was fabricated based on the assembled nanofiber. An electrical transport measurement was conducted on the FET device, showing that ZnO nanofibers are intrinsic n-type semiconductors. The present findings demonstrate that electrospinning can potentially be used as a straightforward and cost-effective means for the assembly of one-dimensional nanostuctures for building integrated nanodevices for various applications, such as transistors, sensors, diodes, and photodetectors.