The optical, electrical and mechanical properties of indium tin oxide (ITO) films prepared on polyethylene terephthalate (PET) substrates by ion beam assisted deposition at room temperature were investigated. The properties of ITO films can be improved by introducing a buffer layer of silicon dioxide (SiO(2)) between the ITO film and the PET substrate. ITO films deposited on SiO(2)-coated PET have better crystallinity, lower electrical resistivity, and improved resistance stability under bending than those deposited on bare PET. The average transmittance and the resistivity of ITO films deposited on SiO(2)-coated PET are 85% and 0.90 x 10(-3) Omega cm, respectively, and when the films are bent, the resistance remains almost constant until a bending radius of 1 cm and it increases slowly under a given bending radius with an increase of the bending cycles. The improved resistance stability of ITO films deposited on SiO(2)-coated PET is mainly attributed to the perfect adhesion of ITO films induced by the SiO(2) buffer layer. (C) 2009 Elsevier B.V. All rights reserved.