An organic light emitting display device includes a display panel including a plurality of pixels each having an organic light emitting element that emits light according to a current corresponding to a data voltage, and a panel driver configured to divide the display panel into first to Mth blocks, calculate an average picture level of each block from data to be displayed in each of the plurality of pixels of each block, convert the data to be displayed by each of the plurality of pixels of each block into the data voltage, and supply the data voltage to each of the plurality of pixels of each block, where the panel driver controls the data voltage to be supplied to an ith block on the basis of the average picture levels of M number of blocks previous to the ith block, where i is a natural number from 1 to M.