Titanium metal development with bone-bonding ability has an increasing demand because of its good properties in clinical applications. Apatite formation on the surface of metal can easily form the bond contact to living bone. The apatite formation can be assessed in vitro using a simulated body fluid (SBF) that has almost equal compositions of inorganic ions to human blood plasma. Galvanostatic intermittent titration technique (GITT) is used to investigate the growth of apatite on chemically treated pure titanium pretreated in NaOH and in C2O4H2 at different periods of time. Scanning electron microscopy (SEM), electron dispersive X-ray analysis (EDX) of titanium surface and solution analyses confirmed the apatite formation and its growth is dependant on time. From GITT, SEM, and calcium ion depletion in the SBF, both pretreatments of C2O4H2 and NaOH were suitable methods for providing the metal implant with bone-bonding ability. However, X-ray diffraction showed that calcium phosphate could form only on the NaOH-pretreated titanium. The TiH2 is one of the key factor responsible for the growth of apatite on titanium surface. (C) 2007 Elsevier B.V. All rights reserved.