Indium nitride (InN) thin films were prepared by a r.f. plasma-assisted reactive ion-beam sputtering deposition (R-IBSD) technique at room temperature. The film deposition rate and the structure of the InN thin films deposited were measured by means of X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). XPS O1s signal intensity of the deposited film decreased considerably with the decrease of the base pressure, and it became negligibly low using an additional source N2 gas purification. In XRD patterns of almost all films deposited, some diffraction peaks due to metallic indium together with a weak diffraction peak due to wurtzite-type (0002)InN reflections, were observed. When the r.f. power was introduced to generate the plasma around the substrate, the XPS signal intensity of the NIn bond and XRD (0002)InN peak intensity became much stronger than those without the r.f. plasma-assisted technique.