TiO2 nanoparticles-deposited on hydroxyapatite (HAp) have been successfully synthesized by direct (single step) hydrothermal treatments of a CaCO3 suspension in a H3PO4 solution with 10 vol% TAS-FINE (titanium amine complex) at 150 degrees C for 6 h or 120 degrees C for 12-24 h under nearly neutral pH conditions. The obtained products were characterized by XRD, SEM-EDX, visible, Raman, and TEM. The XRD and Raman results showed the formation of HAp and TiO2 anatase phases under these hydrothermal conditions. SEM and TEM observations revealed that anatase TiO2 nanoparticles with the size of about 10 nm were deposited on the surfaces of the HAp crystals.