An organic light emitting display device, including pixels positioned at crossing regions of scan lines and data lines and a bias voltage supply configured to supply bias voltages to the pixels. Each of the pixels includes an organic light emitting diode (OLED), a first transistor coupled between a first power supply and the OLED and driven in a saturation region by a corresponding one of the bias voltages to supply a set current to the OLED, a second transistor coupled between the first power supply and the OLED and driven in a linear region by a data signal supplied from a corresponding one of the data lines to turn on or off, and a second capacitor coupled between a gate electrode of the first transistor and the first power supply.