An organic light emitting display device compensates for a variation of the threshold voltage of a driving transistor. A scan driver and a data driver drive a plurality of pixels. A pixel of the pixels includes an organic light emitting diode, four transistors, and two capacitors. A first transistor controls a current to the organic light emitting diode. Second and third transistors are coupled between a data line from the data driver and a gate electrode of the first transistor. A fourth transistor is coupled between a reference power supply and the gate electrode of the first transistor. The two capacitors are coupled between the organic light emitting diode and respective electrodes of the third transistor.