We report the first demonstration of a flexible one diode-one resistor (1D1R) resistive-switching (RS) memory cell capable of high-density crossbar array implementation at an extremely low cost. A Ti/TiO 2/Pt diode with a large rectifying ratio and a stable Ni/HfO 2/Pt unipolar RS memory element have been fabricated on a polyimide substrate using only room-temperature processes. No significant degradation of the rectifying ratio of the TiO 2 diode and the cycling variations, retention, and read disturb immunity of the HfO 2 memory was observed in the bending state. The series 1D1R cell shows highly reproducible unipolar RS because of the low reset current of the HfO 2 memory, which greatly mitigates the adverse effect of diode series resistance. Furthermore, the 1D1R cell can effectively suppress read interference and realize a crossbar array as large as 512 kbit.