We report the effect of the outgassed moisture depending on main roll temperature from polymer substrate on the electrical and optical properties of indiumtin oxide (ITO) films preparedwith roll-to-roll sputtering for use as transparent electrodes. The ITO films deposited with a highmain roll temperature of 80 degrees C were found to exhibit an amorphous structure and the post-annealing process did not improve their electrical conductivity or optical transmittance. After the outgassing processwas performed 6 times in the roll-to-roll sputtering chamber, the optimized sheet resistance of the ITO thin filmwas improved from95 Omega/square to 78 Omega/square. We found that the structural and electrical properties of the ITO films are strongly dependent on the outgassed moisture during deposition. (C) 2017 Elsevier B.V. All rights reserved.