An organic light-emitting display device includes: an organic light-emitting display panel including: a plurality of subpixels including: an organic light-emitting diode (OLED), a driving transistor (DT) driving the OLED including a first transistor between a first node of the DT and a data line, and a second transistor (T2) between a second node of the DT and a reference voltage line having a reference voltage (RV) applied, a sensor, and a sampling switch, wherein, during an OLED short detection period for detecting a short circuit between the first electrode and a second electrode of the OLED: the DT and the first transistor are off, when the T2 is turned off, the RV line is initialized when the RV is applied thereto, after the T2 is turned on, the sampling switch is turned on to connect the sensor and the RV line, and the sensor measures the RV line voltage.