A pixel of an organic light emitting display device includes a transistor, an organic light emitting diode, and a common line. The organic light emitting diode includes a first common layer, an organic light emitting layer disposed on the first common layer, and a second common layer. The common line is disposed between the first common layer and the second common layer to make electrical contact with the first common layer. The common line is supplied with a reference voltage to prevent the organic light emitting diode from generating light by leakage current in the transistor.