A pixel circuit and an organic light emitting display using the same that decrease crosstalk due to a leakage current in an off-region of a pixel switching device to an undetectable (or invisible) level, and compensate for a variation in threshold voltages within itself to provide for uniform brightness. The pixel circuit includes: a first transistor adapted to supply a current corresponding to a voltage applied to a gate thereof to an organic light emitting device; a second transistor adapted to supply a data voltage to a first electrode of the first transistor in response to a first scan signal; a third transistor adapted to connect a second electrode of the first transistor with the gate of the first transistor; and a capacitor adapted to store a voltage corresponding to the data voltage when the first scan signal is applied to the second transistor, and adapted to supply the stored voltage to the gate of the first transistor for the organic light emitting device to emit light.