An organic light emitting diode (OLED) display device includes an OLED display panel having gate lines, data lines intersecting the gate lines, and a plurality of pixels connected to the gate lines and the data lines. A timing controller receives an image signal of a plurality of frames and outputs image data based on the plurality of frames. A data driver generates a data signal voltage corresponding to the image data output from the timing controler. When the image signal includes a black image signal to one pixel of the plurality of pixels that continues for at least a predetermined plurality of frames, the timing controller outputs a first image data in which the black image signal has been converted to a first gray level value that is greater than a gray level value of the black image signal.