Biphase composites of hydroxyapatite (HA) and P-tricalcium phosphate, (TCP) with various phase compositions have been obtained by controlling the molar ratio of Ca(HPO4).2H(2)O and CaCO3 at an appropriate value between 1.5 and 2.0. In this work, biphase composites of HA and beta-TCP with various phase compositions were prepared from the uncalcined Ca(H2PO4)(2).H2O and CaCO3 mixtures. The thermal properties of uncalcined raw materials were investigated using DTA/DSC/TG. The kinetic parameters of dehydration and decomposition for uncalcined Ca(H2PO4)(2).H2O/CaCO3 mixtures were also evaluated by non-isothermal differential thermal analysis (DTA) techniques.