An organic light emitting display device includes: a substrate; a thin film transistor (TFT) on the substrate and including an active layer, a gate electrode, a source electrode, and a drain electrode; an organic light emitting device including a pixel electrode that contacts at least one of the source electrode or the drain electrode of the TFT, an interlayer including a light emitting layer, and a counter electrode facing the pixel electrode, the pixel electrode, the interlayer, and the counter electrode being stacked; and a cathode contact part including a first contact layer and a second contact layer, the first contact layer being at a same layer as the active layer and being doped with ion impurities, the second contact layer including a same material as the source electrode and the drain electrode and coupling the first contact layer and the counter electrode to each other.