A radio-frequency sputtering deposition method was applied to prepare indium tin oxide (ITO) on a plastic substrate, polyethylene terephthalate (PET). The correlation of deposition conditions and ITO film properties was systematically investigated and characterized. The optimal ITO films had a transmittance of over 90% in the visible range (400-700 nm) and a resistivity of 5.0 x 10(-4) Omega-cm. Sequentially alpha-napthylphenylbiphenyl diamine, tris-(8-hydroxyquinoline) aluminium, and magnesium-silver were thermally deposited on the ITO-coated PET substrate to fabricate flexible organic light-emitting diodes (FOLEDs). The fabricated devices had a maximum current efficiency of similar to4.1 cd/A and a luminance of nearly 4100 cd/m(2) at 100 mA/cm(2). These values showed that the FOLEDs had comparable performance characteristics with the conventional organic light-emitting diodes made on ITO-coated glasses with the same device configuration. (C) 2004 Elsevier B.V. All rights reserved.