Objective: evaluation ofthe flexural strength of heat cured acrylic resinthat incorporated with different concentrations of (Titaniumdioxide/Quercetin) nanocomposite particles by comparing with conventional heat cured acrylic resin. Materials and methods: flexure strength test is applied to a total of twenty specimens thatare divided into four main groups according to the percentage of the added Nano material used, then Scanning of the fractured surface by electron microscope. Results: Regarding theflexural strengththere was a statistically remarkable decrease for all modified groups compared with the control group. Conclusion:The concentrationof nano (TiO2/Quercetin) added to PMMAsignificantly affected the mechanical properties of PMMA.Flexurestrengthhave not significantly improved in the modified groups when compared to the control group.