An organic light-emitting display device which is transparent by improving a transmittance in transmitting regions and which reduces a voltage drop in an opposite electrode comprises: a substrate having a transmitting region and pixel regions separated from each other by the transmitting region; thin film transistors positioned on the substrate and disposed in the pixel regions, respectively; a passivation layer covering the thin film transistors, formed in the transmitting region and the pixel regions, and having a first opening formed in a location corresponding to at least a portion of the transmitting region; pixel electrodes formed on the passivation layer so as to be electrically connected to the thin film transistors, respectively, located in the pixel regions, and disposed so as to overlap and cover the thin film transistors, respectively; an opposite electrode facing the pixel electrodes, formed so as to be able to transmit light, and located in the transmitting region and the pixel regions; an organic emission layer interposed between the pixel electrodes and the opposite electrode so as to emit light; and a conduction unit formed of a conductive material, disposed so as to overlap with the first opening, and contacting the opposite electrode.