Nickel nanostructures prepared by various methods have received considerable attentions due to their numerous applications. In this study, one-dimensional nickel nanowires (NiNWs) were synthesized by the reduction of nickel (II) chloride in polyol medium. Poly (vinylpyrrolidone) (PVP) served as the surfactant and hydrazine hydrate was used as the reductant. The effects of different experimental parameters, i.e. concentration of Ni2+, volume of N2H4, concentration of PVP and reaction temperature on the formation and morphology of NiNWs were studied. The structure, composition and surface morphology of the materials were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that the morphology as well as the diameter of NiNWs could be effectively controlled by adjusting parameters of the synthesis process.