Nanostructured tin oxide films were prepared by depositing different sols using spray pyrolysis in a novel technique, the so-called spray-gel process. SnO2 sols were obtained from tin alkoxide Sn(t-OAm)4 or tin tetrachloride (SnCl4 5H2O) precursors and stabilized with ammonia or tetra-ethyl ammonium hydroxide (TEA-OH) as peptizers. Xerogels from the different sols were obtained by solvent evaporation under controlled humidity. The Relative Gelling Volumes (RGV) strongly depend on the type of precursor. Xerogels obtained from inorganic salts gelled faster, while, as determined by TGA, occluding a significant amount of volatile compounds. Infrared spectroscopic analysis was performed on raw and annealed xerogels (500 °C, 1h). Annealing removes ammonia or alkyl ammonium hydroxide, increasing the number of Sn-O-Sn bonds. SnO2 films were prepared by spraying the sols for 60 min onto glass an...