The pixel circuit of an organic light emitting display includes a first transistor to a seventh transistor, a first capacitor, a second transistor and an organic light emitting diode. The first capacitor stores the data signal from the first, second and third transistors, and the second capacitor stores the threshold voltage of the fourth transistor from the fifth transistor. Voltages stored in the first and second capacitors are combined by the sixth transistor, and the fourth transistor generates a driving current corresponding to a combined voltage of the voltages stored in the first and second capacitor. The seventh transistor transmits the driving current and the organic light emitting diode emits light corresponding to the driving current.