Provided is an organic light emitting diode (OLED) display device, including: a substrate; a semiconductor layer on the substrate; a gate insulating layer on the substrate with the semiconductor layer; a gate electrode on a region of the gate insulating layer corresponding to the semiconductor layer and insulated from the semiconductor layer; source and drain electrodes connected to the semiconductor layer; metal layers on the source and drain electrodes, spaced a distance apart from each other, and including nickel; a passivation layer over the gate insulating layer; a first electrode on the passivation layer, and electrically connected to the metal layers; an organic layer on the first electrode; and a second electrode on the organic layer.