A porous silicon-incorporated hydroxyapatite has been prepared using natural coral as a calcium source to obtain a biomaterial having a good biocompatibility. Si-incorporated hydroxyapatite has been prepared by hydrothermal treatment in 2 M (NH4)(2)HPO4 and solvothermal treatment in silicon acetate saturated acetone solution at 180 degrees C of the natural coral repeatedly. From the XRD analysis, it was confirmed that the single-phase hydroxyapatite containing silicon has formed without revealing the presence of extra phases related to silicon dioxide or other calcium phosphate species. Compressive strength of the porous silicon-incorporated hydroxyapatite was 5.5 MPa and silicon content was ranged from 0.12% to 0.19% by weight. SEM and EDS investigation confirmed the presence of silicon in the framework of hydroxyapatite structure. (c) 2005 Published by Elsevier B.V.