Tin-doped In2O3 (indium-tin-oxide) transparent conducting films are widely used as electrodes of liquid crystal displays and low-E windows. In the present study, a systematic TDS study was undertaken for ITO films fabricated by various deposition processes; such as PVD, dip coating and spray deposition. Water vapor was the main gas evolved from the films; gas evolution from the silicon substrate was negligible. The evolution proceeded via two steps at approximately 373 and 473-623 K. The amount of the evolved water was in the order: (dip-coated film)>(PVD films)> (spray-deposited film). This order was identical to that of the film's resistivities.