Bioactive nano-structured titanate layers were fabricated on the surface of Ti-based bulk metallic glass (BMG) using a hydrothermal-electrochemical method. A constant electric current of 0.5 mA/cm2 was applied to the Ti 40Zr10Cu36Pd14 substrate using sodium hydroxide aqueous solutions of 1.0 mol/L as an electrolyte. The morphology of the nano- structured layers depended on the temperature during the hydrothermal-electrochemical treatments. The surface area of a sample 1 cm 2 in area increased from 185 to 325 cm2 with the increase in temperature from 90 to 150°C. The as-prepared samples with amorphous sodium titanate surface layers having a nanomesh structure were immersed in simulated body fluid (SBF). The growth of hydroxyapatite crystallite was observed only for the sample treated at 150deg;C having a surface area larger than 300 cm2.