The gas sensor is essential to monitoring dangerous gases in our environment. Metal oxide (MO) gas sensors are primarily utilized for flammable, toxic and organic gases and O₃ because of their high sensitivity, high response and high stability. Tungsten oxides (WO₃) have versatile applications, particularly for gas sensor applications because of the wide bandgap and stability of WO₃. Nanosize WO₃ are synthesized using the hydrothermal method. Asprepared WO₃ nanopowders are in the form of nanorods and nanorulers. The crystal structure is hexagonal tungsten bronze (MxWO₃, x =< 0.33), characterized as a tunnel structure that accommodates alkali ions and the phase stabilizer. A gas detection test reveals that WO₃ can detect acetone, butanol, ethanol, and gasoline. This is the first study to report this capability of WO₃.