Provided are an organic light emitting display device coupled to a photoelectric transistor. The organic light emitting display device includes an anode and a cathode separated from each other, a plurality of organic material layers formed between the anode and the cathode and including an organic light emitting layer, a light source applying an excitation pulse to the organic material layers, and a light receiving unit measuring changes in photoluminescence (PL) signals that are emitted from the organic material layers.