Herein, we report improved NO2 and O2 gas sensitivity of spin coated ZnO thin film treated with Ar and N2 plasma for different time intervals (15, 30 and 45minutes). X-ray diffraction study suggested no change in the structure while the SEM investigation showed major change in topography of plasma irradiated films. The I-V curves are indicative of increase in conductivity and NO2 and O2 gas sensitivity. The oxygen sensitivity for 45 min Argon and oxygen plasma treated ZnO thin films showed highest sensitivity compared to pristine ZnO films. The improved sensitivity is attributed to the modified surface
morphology of plasma treated ZnO thin films.