The aim of this paper is to present the gas sensing performance of In2O3 and Sn-doped In2O3 films prepared by a novel technique, i.e., Electrostatic Spray Deposition technique. The morphology and the microstructure studies reveal that the films are porous comprising grains in the nanometer range and crystallizing in the cubic structure. The present films prove to be sensitive to low H2S concentrations (1–10 ppm) at low operating temperature (200 °C). Undoped films present a very high sensitivity to H2S, compared with doped films, and a negligible response to NO2 and SO2. Sn dopant introduced in In2O3 causes a great sensitivity decrease in H2S response, and, on the contrary, a slight increase in NO2 and SO2 response.