Amorphous calcium silicate coating on a metallic titanium substrate for hard tissue replacement was prepared by a sol-gel method. Calcium silicate film was deposited on a titanium substrate by a spin-coating technique and subsequently heated at 500°C for 2 h in air. The deposited film, which was dense, had thickness of about 800 nm and strongly adhered to the substrate. Biomimetic apatite-forming ability of the deposited films was examined by soaking in simulated body fluid (SBF). Thin film X-ray diffractometry and scanning electron microscopy showed the formation of apatite on the surface after 10 days of soaking in SBF.