An organic light emitting display device includes a substrate. A buffer layer is disposed on the substrate. The buffer layer includes a first opening exposing an upper surface of the substrate in a bending region. Pixel structures are positioned in a pixel region on the buffer layer. A fan-out wiring is positioned in the peripheral region and the pad region on the insulation layer structure such that the upper surface of the substrate and the first portion of the buffer layer are exposed. A passivation layer is disposed on the fan-out wiring, side walls of the insulation layer structure adjacent to the bending region, and the first portion of the buffer layer. The passivation layer includes a third opening exposing the upper surface of the substrate in the bending region. A connection electrode is positioned in the bending region on the substrate.