An organic light emitting diode display device (OLED display device) having uniform electrical characteristics and a method of manufacturing the same. The OLED display device includes: a substrate; a semiconductor layer disposed on the substrate, and including source and drain regions and a channel region formed using metal induced lateral crystallization (MILC); a gate insulating layer for electrically insulating the semiconductor layer; a gate electrode disposed on the gate insulating layer; an interlayer insulating layer for electrically insulating the gate electrode; a thin film transistor (TFT) including source and drain electrodes that are electrically connected to the source and drain regions of the semiconductor layer; a first electrode for a capacitor disposed on a region of the substrate to be spaced apart from the TFT and formed using a metal induced crystallization (MIC); the gate insulating layer for electrically insulating the first capacitor electrode; a second electrode for the capacitor disposed on the gate insulating layer; a planarization layer disposed on the TFT and the capacitor; a first electrode disposed on the planarization layer; a pixel defining layer disposed on the first electrode; an organic layer disposed on the first electrode and the pixel defining layer, and including at least an emission layer; and a second electrode disposed on the organic layer.