In this study, the solution preparation and the annealing conditions were studied for spin-coated ITO films. Then, the effect of several post-treatment parameters such as H-2 concentration, temperature, and processing time were investigated for the H-2/Ar atmosphere. The properties of thin films were characterized by four-probe measurement set-up, UV-visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). It has been found that seven times deposition of 0.5 M solution including In:Sn with the ratio of 90:10 and annealing the films at 600 degrees C in air for 30 min was the optimum preparation condition for ITO films. Subjecting the ITO films to 10% H-2 containing Ar medium at 300 degrees C for 3 h was found as the most efficient process for post-treatment and as a result of that, approximately 70% efficiency was achieved on the reduction of the sheet resistance without affecting the transmittance of the thin films. (C) 2020 Elsevier B.V. All rights reserved.