In this work, the kinetics of hydroxyapatite (HA) deposition on solid substrates from liquid precursor (simulated body fluid, SBF) is investigated. The surfaces of stainless steel, silicon and silica glass substrates are modified by sequential implantation of Ca and P ions. Three groups of samples of each material: (i) ion-implanted; (ii) ion-implanted and thermally treated at 873 K in air for 60 min; and (iii) untreated are prepared. To investigate the kinetics of the HA deposition, all three groups of samples are introduced at equal conditions into SBF whose supersaturation is maintained during the whole 6-day period of immersion. The layers are analyzed by FTIR and Raman spectroscopy. Both techniques complement each other and show the formation of HA with incorporated CO32- and HPO42- groups. Following the kinetics of the deposition process, it is concluded that the speed of deposition is different on the three materials modified by Ca and P implantation and by oxidation, compared to untreated samples but in order to distinguish clearly the effect of the ion implantation and oxidation the very initial moment of nucleation and layer growth should be more carefully investigated. (C) 2004 Elsevier B.V. All rights reserved.