WO3 nanofibers were synthesized using an electrospinning method and characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The obtained WO3 nanofibers were used as sensitive materials for the detection of NH3. Indirect-heating sensors based on WO3 nanofibers were prepared. When the WO3 nanofiber-based sensors were exposed to 100 ppm NH3 at 500 degrees C, the response is 5.5, and the response and recovery times are 1 and 5 s, respectively. These results indicate that the gas sensors based on WO3 nanofibers express high and fast response and recovery characteristics to NH3, and the WO3 nanofibers are promising sensitive materials for NH3 detecting. (C) 2010 Elsevier Inc. All rights reserved.