An organic light emitting display includes pixels positioned at crossing regions of scan lines, emission control lines, and data lines. Each of the pixels positioned on an ith horizontal line includes an organic light emitting diode (OLED), a first transistor coupled between a corresponding one of power source lines and an anode electrode of the OLED for controlling current supplied to the OLED, a second transistor turned on when a scan signal is supplied to an ith scan line for supplying the data signal from a corresponding one of the data lines to a gate electrode of the first transistor, a third transistor coupled between the first transistor and the corresponding one of the power source lines and having a gate electrode coupled to an ith emission control line, and a storage capacitor coupled between the gate electrode of the first transistor and the anode electrode of the OLED.