A pixel circuit in an organic light emitting device capable of realizing high gradation representation by self-compensating a threshold voltage, and a method for driving the same. The pixel circuit includes an electroluminescent element for emitting light in response to an applied driving current. A first transistor delivers a data signal voltage in response to a current scan line signal. A second transistor generates a driving current to drive the electroluminescent element in response to the data signal voltage. A third transistor connects the second transistor in the form of a diode in response to a current scan signal to self-compensate the threshold voltage of the second transistor. A capacitor stores the data signal voltage delivered to the second transistor. A fourth transistor delivers a power supply voltage to the second transistor in response to a current light-emitting signal. A fifth transistor provides the driving current, provided from the second transistor, for the electroluminescent element in response to the current light-emitting signal.