The effects of post-deposition annealing in different atmospheres, on electrical anti optical properties of sputtered and thermally evaporated indium tin oxide (ITO) films, have been investigated. Significant variations in resistivity, mobility, carrier concentration and transparency were observed. X-ray diffraction patterns (XRD) and scanning electron microscopy (SEM) showed changes in the film grain structures after thermal treatment, Optimum properties were obtained under N-2/H-2 conditions giving resistivity values around 3 x 10(-4) Omega cm and transmittance values more than 90%.