An organic light emitting display device may include a substrate, an anode, an auxiliary electrode, a light emitting structure, a lower cathode, and an upper cathode. The substrate may include a pixel region, a transparent region, and a boundary region between the pixel region and the transparent region. The anode may be on the pixel region. The auxiliary electrode may be on the transparent or boundary regions. The light emitting structure may be on the anode and the auxiliary electrode and extended from the pixel region to the transparent region. The lower cathode may be on the light emitting structure and made thin to increase transmittance. The upper cathode may be on the lower cathode. The thin lower cathode may be electrically connected to the auxiliary electrode via a contact hole which penetrates the light emitting structure so as to reduce a voltage drop.