Low Young's modulus is an important property for metallic biomaterials. Porous materials are advantageous from the point of view of obtaining a lower Young's modulus. However, with a decrease in Young's modulus, the other mechanical properties start deteriorating simultaneously. In comparison with metallic biomaterials, polymers exhibit lower Young's moduli; and thus a polymer filling is a likely option to improve the mechanical properties of porous materials by preventing the stress concentration at the pores without increasing the Young's modulus. Furthermore, certain polymers exhibit intrinsic biofunctionalities. Thus, polymer filling is expected to prevent an increase in the Young's modulus and impart biofunctionalities to porous materials without the deterioration of its mechanical properties. In this study, the pores of porous pure titanium (pTi) were filled with a medical polymer (polymethylmethacrylate: PMMA). The effects of PMMA filling on the mechanical properties of pTi were then investigated.