An organic light emitting display device is disclosed, which may increase sensing accuracy by solving a problem that a difference between sensing data output from sensing units is generated due to a difference in sensing capability between the sensing units. The organic light emitting display device includes a display panel including data lines, scan lines, sensing lines, and pixels connected to the data lines, the scan lines and the sensing lines; a sensing data output unit outputting first sensing data by sensing currents flowing to the sensing lines; a scan driver supplying scan signals to the scan lines; and a source drive integrated circuit (IC) including a data voltage supply unit supplying data voltages to the data lines and a switching unit connecting the sensing lines to the sensing data output unit in a predetermined order.