The preparation and characteristics of flexible indium tin oxide (ITO) electrodes grown on polyethylene terephthalate (PET) substrates are described for use in flexible organic solar cells and prepared using a specially designed facing target roll-to-roll sputtering (FTRS) system. Due to the effective confinement of the high-density plasma between two facing ITO targets, we can deposit the ITO electrode continuously on the PET substrate at a substrate temperature below 50 degrees C without the need of a substrate cooling system, which is used in conventional roll-to-roll sputtering systems. In spite of a low substrate temperature, the FTRS-grown flexible ITO electrode showed a sheet resistance of 42.2 Omega/square, a resistivity of 8.44x10(-4) Omega cm, and a transmittance of 85.41% in the 500-550 nm wavelength range with superior flexibility. Furthermore, the flexible organic solar cell fabricated on the FTRS-grown flexible ITO electrode at optimized conditions exhibited a power-conversion efficiency of 2.43%, which is similar to an organic solar cell fabricated on a reference dc sputter-grown ITO electrode. This indicates that the FTRS technique is a promising continuous-sputtering process for preparing flexible ITO electrodes and can substitute for conventional roll-to-roll sputtering systems for mass production of flexible solar cells.