An organic light-emitting display device including a plurality of pixels. Each of the pixels includes an organic light-emitting diode (OLED), a driving transistor, which has a control electrode connected to a first node, an input electrode connected to a second node, and an output electrode connected to the third node and provides a driving current to the OLED in accordance with a voltage of the control electrode, a sustain capacitor, which is connected to the first node, a first transistor, which controls whether the first and third nodes are to be connected, and a compensation transistor, which has both an input electrode and an output electrode connected to the first node.