This article focuses on the significant increase in the mechanical strength of PMMA (polymethyl methacrylate) that was achieved through the incorporation of multiwall carbon nanotube (MWCNT) and nano-size hydroxyapatite (HA) powders at varied loadings ranging from 0.25 to 0.75 wt%. This study aimed to validate the potential applications of this modified bio-nanocomposite through mechanical investigation and characterization. According to the findings, the incorporation of 0.5 wt% of both HA and MWCNT nanoparticles into the PMMA bone cement powder resulted in increase in the flexural strength of 26.67%, the flexural modulus of 24.32%, the compression strength of 14.58%, and the compression modulus of 50.8%. Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD) are used to investigate the distribution and interaction of reinforced nanoparticles within the PMMA polymer matrix further. Due to this compatibility between fillers and matrix, improvement in mechanical properties is observed in the developed bio-nanocomposite. Overall, the FTIR analysis provided valuable insights into the functional group composition and molecular interactions within the produced nanocomposites, confirming the presence of specific vibrational modes and demonstrating the compatibility between the filler materials and the polymeric matrix.