An organic light-emitting display apparatus includes an organic light-emitting diode, a driving transistor arranged to receive a first driving voltage and to supply a driving current to the organic light-emitting diode, a data line arranged to transfer a sustain voltage and a data voltage, a sensing transistor which is connected to the data line, and which is arranged to transfer the sustain voltage to an anode of the organic light-emitting diode in response to a sensing control signal, a switching transistor which is connected to the data line, and which is arranged to transfer the data voltage to the driving transistor in response to a scan signal, and a data compensation unit arranged to compensate image data according to characteristic information of the organic light-emitting diode, the characteristic information transmitted to the data compensation unit through the sensing transistor and the data line.