We have studied the lifetime improvement of organic solar cells (OSCs) based on the conjugated polymer:fullerene blends using an ultra-violet (UV) blocking transparent conducting oxide (TCO). Without additional passivation films/layers or changing of structure, the performance of the OSC using UV blocking TCO was comparatively stable under the strong UV exposure. When 30 mW/cm(2) of UV was irradiated for 300 seconds, the V-OC and FF of the OSC without UV blocking TCO decreased to 87% and 64%, respectively. As a result, power conversion efficiency (PCE) decreased to 54%. However, the V-OC and FF of OSC with UV blocking TCO slightly decreased to 96% and 87%, respectively.