An organic light emitting display device. The organic light emitting display device includes a substrate having a pixel region in which pixels are formed and a non-pixel region in which a light sensor is formed, an insulating film formed on the substrate, a first electrode formed on the insulating film and formed of a reflective material reflecting light, the first electrode being formed on the entire surface of the insulating film except for a region between the pixels and a region over the light sensor, a pixel defining film exposing a region of the first electrode and formed on the insulating film, an organic light emitting layer formed on the exposed region of the first electrode, and a second electrode formed on the organic light emitting layer. The first electrode is formed to have a greater area than that of the organic light emitting layer.