SnO 2 nanocrystalline thin films have been deposited on oxidized silicon substrates by spin-coating from a precursor solution, followed by slow thermal annealing in oxygen atmosphere at different temperatures (500 to 900°C). The precursor solution consisted of 1.0 to 2.0 M SnCl 4 ·5H 2 O in isopropanol. It was shown that the concentration of the precursor solution, annealing temperature and heating rate had a significant effect on the structural, optical and electrical properties of the studied thin films. The topography of SnO 2 thin films was examined by scanning electron microscopy (SEM). Furthermore, as-deposited films were characterized by X-ray diffraction (XRD), UV-Vis and impedance spectroscopy.