Abstract: A calcium phosphate self-setting cement is invented by using diffusion controlled solid liquid heterogeneous reaction between tetracalcium phosphate (Ca4(PO4)2O, TTCP) fine powder and solution of di-potassium hydrogen phosphate (K2HPO4). Fine powders of tetracalcium phosphate is introduced into the di-potassium hydrogen phosphate solution and homogenized well to form a cement paste. The cement paste was allowed to set at room temperature (25±5° C.). In the cement paste calcium is leached from the tetracalcium phosphate (TTCP) fine particles as Ca(OH)2 into the aqueous phase. Leaching of calcium continues until the Ca/P ratio changes from 2 to 1.67, which corresponds to hydroxyapatite. Calcium hydroxide thus formed reacts with the phosphate ions (p043?) that exist in the liquid phase, and the reaction leads to in-situ precipitation of hydroxyapatite as the reaction product, which leads to interparticle entanglement in the cement paste, thereby forming self-setting bone cement.