In this contribution, the Co doped SnO₂ transparent semi-conducting films are prepared by spray pyrolysis technique and the influence of N₂-and Ar-ambient annealing on their structural, electrical and optical properties are studied. The SnO₂:Co thin films were deposited on the glass substrate at substrate temperature of 480 ˚C using an aqueous-ethanol solution consisting of tin and cobalt chloride. Doping levels of cobalt chloride have been changed from 0 to 14 wt. % in solution. Analysis of the X-ray diffraction patterns show that ‘a’ and ‘V’ parameters of the tetragonal unit cell decrease with increasing impurity content, while c parameter pass through a minimum for a acceptor dopant concentration of 8 wt. % or [Co]/[Sn] atomic ratio equal to 20 atm.% in solution. The N₂-and Ar-ambient annealing causes increase of the electrical resistivity, band gap energies, and transparency of the cobalt doped samples.