An organic light emitting display and a method for driving the same are disclosed. The organic light emitting display includes a display panel, a data driver supplying a data signal to the display panel, a memory which is positioned inside or outside the data driver and includes at least two banks, and a sensing circuit unit which measures a threshold voltage of at least one driving transistor included in the display panel and provides compensation data. The data driver separately writes and reads previous compensation data and new compensation data provided by the sensing circuit unit in the at least two banks of the memory.