Objectives: The aim of this study was to synthesize visible light activated titanium dioxide (TiO 2) nanoparticles using titanium nitride (TiN) by solution route to determine its antimicrobial activity against Staphylococcus aureus when combined with heat cure polymethyl methacrylate denture base resins (PMMA) in three different combinations. Methods: Visible light activated as-prepared TiO 2 photocatalyst was synthesized by peroxide based solution route technique using TiN. Part of the as-prepared TiO 2 was annealed and anatase form was obtained. Physical properties of the material were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive Xray spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FTIR). TiO 2 (3 w%, 5 w%)-PMMA composite samples (incorporated, precuring or post-curing coating) and unblended acrylic samples were prepared. They were placed in saline and exposed to light for 1 day, 1 week, 1month, 3 months and 6 months in a halogen light system specially fabricated for this study. Then the samples were subjected to microbiological tests to determine the inhibitory activity against S. aureus. Based on visible turbidity changes in the broth containing samples the antibacterial activity was reported. Statistical analysis of the data was done to interprete the results. Results: XRD, SEM, EDAX and FTIR showed better patterns with anatase form. This material showed consistent and reliable inhibitory activity in all forms when combined with PMMA in three different combinations. The best results were achieved at 3 w% concentration of TiO 2. Conclusion: 3 w% of anatase TiO 2 upon incorporation and postcuring coating with PMMA shows promising inhibitory activity against S.aureus. Clinical significance: To decrease the load of oral microflora on dentures by utilising visible light activated TiO 2 photocatalyst especially in elderly and handicapped denture wearers.