An organic light emitting display includes a display panel including a plurality of pixels, each pixel among the plurality of pixels including an organic light emitting diode (OLED) connected between a first potential driving power having an initial value and a second potential driving power, and a driving thin film transistor (TFT) connected between the first potential driving power and the second potential driving power; a driver integrated circuit (IC) configured to drive the display panel; a power IC configured to apply the first potential driving power to the display panel; and a sensing unit configured to sense changes in driving characteristics of the display panel each time the first potential driving power varies from an initial value of the first potential driving power in a state where the initial value of the first potential driving power and a test pattern are applied to the display panel.