The role of cerium in the formation of stable beta-Ca-3(PO4)(2)/c-CeO2 composites and their structural analysis with varied compositional ratios were investigated. The composite formation was attempted through an in situ precipitation technique, and the gradual structural changes during heat treatments to yield the pure form of beta-Ca-3(PO4)(2)/ c-CeO2 composites was presented. The cerium was found in Ce3+ and Ce4+ oxidation states in composites. Ce3+ prefers to occupy the Ca2+ (1), Ca2+(2), and Ca2+(3) sites of beta-Ca-3(PO4)(2), whereas, beyond the saturation occupancy limit, excess cerium prefers to crystallize in the form of thermodynamically stable cubic ceria (c-CeO2). A uniform expansion of the beta-Ca-3(PO4)(2) unit cell and the delayed allotropic conversion of beta-Ca-3(PO4)(2) -> alpha-Ca-3(PO4)(2) have been detected due to the Ce3+ occupancy at the beta-Ca-3(PO4)(2) lattice. beta-Ca-3(PO4)(2)/c-CeO2 composites exhibited a steady upsurge in the mechanical properties with consistent enhancement of c-CeO2 content in the composites. The overall results from the investigation imply the appropriateness of the beta-Ca-3(PO4)(2)/c-CeO2 composites for applications in hard tissue replacements.