Pure and Ni-doped ZnO nanofibers were synthesized using the electrospinning method. The morphology, crystal structure and optical properties of the nanofibers were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy, respectively. It is found that Ni doping does not change the morphology and crystal structures of the nanofibers, and the ultraviolet emissions of ZnO nanofibers present red shift with increasing Ni doping concentration. C2H2 sensing properties of the sensors based on the nanofibers were investigated. The results show that the C2H2 sensing properties of ZnO nanofibers are effectively improved by Ni doping, and 5 at % Ni-doped ZnO nanofibers exhibit a maximum sensitivity to C2H2 gas. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.