This study was intended at evaluating the impact of adding gold nanoparticles(AuNPs) on the characteristics of heat-cured acrylic denture base resin. Heat cured polymethyl methacrylate (PMMA) samplings, each one had a dimension of 50±1 mm length, 30±1 mm width, and thickness of 0.5±0.1 mm, enclose various sizes (10and 20 nm) of gold nanoparticles were formulated, where free nanoparticle samples were deemed as the control group(N=6 specimens for each group). Flexural strength, color changes, surface roughness, and hardness of all specimens were then assessed. Data were amassed, statistically evaluated, and tabulated. It was fulfilled that statistically significant decreases in the flexural strength were observed with the increase in gold nanoparticle size, where group 3(with 20% nanogold particle size) was peaked. However, no significant differences in PMMA color changes, superficial roughness, and hardness were observed in the groups covering various sizes of AuNPs. it was concluded that The flexural strength of heat-cured PMMA-resin showed significantly decreases with the addition of AuNPs, particularly with the particle's sizes of 20nm.