An organic light emitting display device includes a display panel, a data driver, and a scan driver. The display panel includes sub-pixels. The data driver supplies a data signal to the sub-pixels. The scan driver supplies a scan signal for controlling a switching transistor of each sub-pixel, and a sensing signal for controlling a sensing transistor of each sub-pixel. The sensing transistor has a turn-on time for detecting whether a short has occurred between at least two electrodes of a switching transistor in response to a sensing signal.