Disclosed is an organic light emitting 
display device including a pixel connected to a data line, a gate line group, and a 
reference line. The pixel includes an organic 
light emitting diode (
OLED), a driving 
transistor configured to control a current flowing in the 
OLED, a first switching 
transistor configured to selectively supply a data 
voltage to a first node, a second switching 
transistor configured to selectively supply an initial 
voltage to a second node, a third switching transistor configured to selectively connect a third node to the 
reference line, a fourth switching transistor configured to selectively connect the first node to the third node, a first 
capacitor connected between the first and second nodes to store a 
threshold voltage of the driving transistor, and a second 
capacitor connected between the first and third nodes to store the data 
voltage supplied through the first switching transistor.