The purpose of this study was to evaluate the effect of nano gold (AuNps) reinforcement of polymethyl methacrylate (PMMA) and polyamide flexible denture base materials on the impact strength. Denture base specimens were fabricated from Acrostone PMMA, AuNps reinforced PMMA, thermopress flexible polymeric (bre. flex 2nd edition) and AuNps reinforced flexible polymeric resin. The impact strength was evaluated as one of the most important mechanical properties of the denture base materials. Sig-nificant difference was observed between all denture base materials tested. The AuNps reinforcement of the bre. Flex polymeric denture base material improved impact strength.