An organic light emitting display device includes: a panel having sections and blocks, pixels included in the blocks to control an amount of current flowing from a first power source to a second power source via organic light emitting diodes; a data driver to receive data, and generate the data signals; a sensing unit connected to the power supply unit, and to detect an amount of current flowing in each of the blocks; and a timing controller to generate a correction value to adjust the data in view of the amount of current.