An organic light emitting display and a method for driving the organic light emitting display. The organic light emitting display includes a display unit, a data accumulator, and a data compensator. The display unit is configured to be driven by image data. The data accumulator is configured to compress and accumulate first data corresponding to a first portion of the image data for driving a first region of the display unit, identify a second region of the display unit from the first region by analyzing the accumulated first data, and compress and accumulate second data corresponding to a second portion of the image data for driving the second region with a compression ratio based on a size of the second region. The data compensator is configured to compensate the image data based on the accumulated first and second data.