Hydroxyapatite (HAP) crystalline thin-coatings have been grown using a right angle RF magnetron sputtering approach at room temperature. The surface structural information of these biocompatible coatings at nanometer scales was obtained by glancing-incidence X-ray diffraction (GIXRD) with synchrotron radiation. The GIXRD spectra were obtained by fixed incidence theta angles at 0.5 and 1 degree. Structural profile analyses were performed over these nano-coating layers with reduced substrate interference. The coating thickness was calibrated by specular X-ray reflectivity (XRR) curves. Experiments have been performed on thin-coatings of HAP sputtered on silicon wafers and acid etched titanium discs at room temperature. GIXRD analysis has shown that all the principal peaks are attributed to a crystalline HAP. Previous tests of biocompatibility with osteoblasts cells have been encouraging studies on the surface of hydroxyapatite thin coatings prepared by opposing RF magnetron sputtering approach, as a promising candidate for bioimplant materials.