During the last decade, due to its excellent electrical, mechanical and thermal properties of chemically modified graphene has been extensively studied for many applications, such as polymer composites, energy-related materials, biomedical applications and sensors. The aim of this work is to evaluate the gas sensing performance of niobium oxide (Nb2O5) nanoclusters deposited onto few-layers graphene powder by magneton sputtering. Two different samples were prepared by changing electrical power of deposition. The materials were deeply morphologically, structurally and chemically characterized. Finally, they were deposited onto alumina substrates and their sensing properties were investigated vs. different gases, showing good sensing performance vs. ppm concentrations of NO2 at room temperature.