This paper discusses the durability of the DC-Magnetron sputtered Indium Tin Oxide (ITO) thin films on 127-mu m Poly Ethylene Terephthalate substrate under harsh environmental conditions and high cyclic bending fatigue. Two sets of experiments were conducted on a 60 Omega per square ITO sheet. The first set of experiments was conducted on samples with different temperature and humidity combinations while being subjected to cyclic bending fatigue loadings. The other set of experiments was conducted on samples with the same combinations of temperature and humidity but without bending fatigue loading. Design of experiments tool was used to study the effect of temperature, humidity, bending fatigue and the interaction among them on the percent change in electrical resistance of the ITO film. It was found that bending fatigue is the dominant factor to the electrical failure of ITO thin film. The failure was also influenced by temperature and humidity, especially combined high temperature and high humidity. Therefore, it is suggested that controlling the environmental factors during the roll to roll manufacturing process is crucial on quality of the products. Published by Elsevier B.V.