Abstract: An organic light-emitting display for improving an aperture ratio and increasing lifespan includes an organic light-emitting display panel in which pixel cells are formed, a gray-scale converter configured to convert a gray-scale of a pixel data signal by multiplying the pixel data signal which drives the pixel cells by a scale parameter, and a scale parameter generator configured to generate the scale parameter, wherein the scale parameter generator generates a scale parameter of a present frame by increasing or decreasing a scale parameter of a previous frame in proportion to a current difference obtained by subtracting a reference current value from a total current value of the pixel data signal which is gray-scale converted from the previous frame.