An organic light-emitting display device, including a display unit including a plurality of pixels each having an organic light-emitting diode (OLED), a controller configured to accumulate image data of each frame and to generate compensated image data using a degradation compensation method determined, based on the accumulated image data, to compensate for the degradation of the OLED of each of the pixels, and a data driver configured to generate a data voltage according to the compensated image data and to provide the data voltage to the pixels.