An organic light emitting display includes a scan driving unit applying scan signals and light emitting control signals through a plurality of scan lines and light emitting control lines, a data driving unit applying data signals through a plurality of data lines, a power supply supplying an electric power to a plurality of power supply entries, a pixel unit including a plurality of pixels receiving the plurality of scan signals, light emitting control signals, data signals, and the electric power to display an image, the pixel unit being divided into a plurality of regions corresponding to the plurality of power supply entries, and a current limiting circuit using data current values accumulated region by region in the plurality of regions to output current limiting signals for limiting brightness of the pixel unit.