This study aimed to investigate the formation and properties of magnesium (Mg)-substituted tricalcium phosphate, beta-TCMP, its properties and potential as biomaterial for bone repair. beta-TCMPs were prepared and characterized using x-ray diffraction, FT-IR and SEM. Dissolution properties were determined in acidic buffer. beta-TCMP discs were implanted in surgically created holes in femoral and tibial diaphyses of rabbits. Results demonstrated that the formation of beta-TCMP and Mg incorporation in beta-TCMP were dependent on reaction pH, temperature and solution Mg/Ca ratios. Sintered beta-TCMP was significantly less soluble than beta-TCP. Implanted unsintered beta-TCMP showed osteoconductive properties associated with new bone formation. This study suggests that beta-TCMP (sintered or unsintered), alone or in combination with other calcium phosphates, may be useful as biomaterials for bone repair and maybe useful in cases where slower biodegradation than that of beta-TCP is desired