This work was carried out to comparatively study the reinforcement efficiency of bone ash and bone particles on the mechanical properties of polyester matrix composites in order to investigate the suitability of the materials as biomaterial. Cow bone were procured from an abattoir and sun dried for 4 weeks after which it was crushed with a sledge hammer. A portion was burnt to ashes while others were further pulverized with laboratory ball mill before the two grades were sieved using 75 μm sieve size. Bone ash and bone particle reinforced tensile and flexural composite samples were developed from pre-determined proportions of 2, 4, 6, and 8 %. The samples after curing were striped from the moulds and were allowed to further cure for 3 weeks before tensile and flexural tests were performed on them. The tensile test result showed that, 8 wt % bone particle reinforced polyester composites has higher tensile properties except for modulus of elasticity where 8 wt % bone ash particle reinforced composites has higher value while for flexural test, bone ash particle reinforced composites demonstrate the best flexural properties. The results show that these materials are structurally compatible and being developed from animal fibre based particle, it will also aid the compatibility with the surface conditions as biomaterial.