AbstractTungsten and tungsten oxide films were deposited in a hot filament reactor under flowing argon atmosphere at various filament temperatures, followed by the characterization via scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD). It revealed that both tungsten (W) and tungsten oxide [WO2+x (0≤x<1)] nanorods with diameters in the range of 4-200 nm and lengths up to a few microns can be synthesized. After deposition at higher temperatures (above 2200 °C), the predominant phase in the film was tungsten, while with the filament temperature decreasing, the content of WO2+x increased significantly. It implies that the method applied in the present study enables the synthesis of high purity tungsten or tungsten oxide nanorods possible.