An organic light-emitting display device may include a first pixel, a first data line, a first scan line, a data driver, and a scan driver. The first pixel unit may include a sensing transistor and a scan transistor. The data driver may be electrically connected to the scan transistor through the first data line. The scan driver may be electrically connected to the scan transistor through the first scan line. The scan transistor may be turned on during a first period and a second period. The sensing transistor may be turned on during a third period between the first period and the second period. The first period, the second period, and the third period are included in one frame.