Objective: This study was aimed to evaluate the effect of incorporation of two-different nanoparticles (NPs); silica (SiO 2), and zirconia (ZrO 2) on flexural strength, impact strength, as well as, water sorption and solubility of thermoplastic resin material. Materials and Methods: Two nanoparticles SiO 2-NPs, and ZrO 2-NPs (Nano-gate Company, Egypt) were incorporated into thermoplastic resin with different concentration (1.5 and 7 wt.%). This study was divided into five main groups; unmodified "control group" and four modified groups according to the type and concentration of the incorporated nanoparticles. Results: The results of this study revealed that the incorporation of 1.5 wt.% SiO 2-NPs significantly improves the flexural strength of thermoplastic resin. While the incorporation of SiO 2-NPs and ZrO 2-NPs nanoparticles insignificantly decreases its impact strength. However, they significantly increase water sorption and solubility of thermoplastic resin. Conclusion: The incorporation of nanoparticles into thermoplastic resin at different concentrations could negatively affect its flexural strength, impact strength, as well as its water sorption and solubility.