This paper presents the performance of a nanostructured tungsten trioxide (WO₃) based bottom gate field effect transistor as a highly responsive gas sensor. The fabrication process followed is scalable and semiconductor industry compatible. Complete material and electrical characterization of the device was performed which shows WO₃ nano-clusters and ambipolar nature of the WO₃ based transistor. Sensing studies were carried out in presence of volatile organic compounds (VOCs) of which maximum response was given to acetone. Dynamic response was taken to demonstrate real time sensing.