We have studied the mechanical stability of poly-Si thin-film transistor on 50 mu m-thick flexible metal foil with a field-effect mobility of 81.2 cm(2)/V s, a threshold voltage of - 2.4 V, and an on/off current ratio of 10(6). We have measured the electrical properties under various compressive and tensile strains by changing the bending radius of the base metal foil. We have found that the TFT is stable until the bending radius of 50 mm which corresponds to the strain of similar to 1.4%. (c) 2007 Elsevier Ltd. All rights reserved.