Introduction: Tungsten oxide is an n-type semiconductor which possesses the bandgap of 2.6 __ampersandsignndash; 2.8 eV at room temperature. Additionally, tungsten oxide has the absorption capacity of 480 nm in the visible region resulted from its photocatalytic property. Objective: To synthesize and evaluate tungsten oxide nanoparticles for microbial inhibition. Methods: Microwave-assisted synthesis of tungsten oxide nanoparticles was carried out by solvothermal route for the development of antibacterial agent. 1 M Sodium Tungstate Dihydrate was dissolved in 100 mL distilled water which was then mixed with 20 mL of 0.1 M NaOH and the Conc. HCL was added into the reaction mixture. The precipitation of yellow colour was collected and rinsed with purified water three times. During 8 hours at 60oC and 4 hours, the precipitate having undergone drying and calcination to get tungsten oxide powder. Results: The yellow colour precipitate was obtained after the reaction, which was characterized by UV- Vis Spectroscopy and Scanning Electron Microscopy (SEM). The __ampersandsignlambda;max was found to be at 364 nm and bandgap calculated as 3.41 eV. Conclusion: Antibacterial efficacy was determined by anti-well diffusion assay against E. coli and Pseudomonas Aeruginosa. The bacterial cultures were found to be sensitive for WO3 NPs at a concentration of 1000 __ampersandsignmicro;g/mL. The E. coli was more sensitive for WO3 NPs compared to Pseudomonas Aeruginosa.