A display device includes: a display unit including a plurality of pixels connected to a plurality of scan lines and a plurality of data lines and emitting light according to corresponding image data; a dummy pixel connected to a dummy scan line and a dummy data line; and a compensation image data generator calculating a compensation amount according to an accumulation light emitting time of the first organic light emitting element to detect the compensation amount corresponding to each accumulation light emitting time of a plurality of second organic light emitting elements of the plurality of pixels by using a decreasing amount of luminance corresponding a resistance of a first organic light emitting element according to an accumulation light emitting time of the first organic light emitting element of the dummy pixel, and compensating the corresponding image data according to the detected compensation amount.