An organic light emitting diode (OLED) display is disclosed. One aspect includes a pixel unit including a plurality of pixels formed at portions at which scanning lines and data lines intersect with each other; a scan driver for supplying scan signals to the scanning lines. The OLED display further comprises a data driver for supplying data signals to the data lines; and a data compensation unit changing the input data using a correction coefficient stored as a unit of a pixel block including a plurality of pixels and supplying the changed input data to the data driver. In such OLED display, the pixel block is divided so that the number of pixel arranged in the first direction is different from the number of pixel arranged in the second direction which intersects with the first direction.