A pixel circuit for an organic light emitting display includes: a fourth NMOS transistor including a gate electrode coupled to a first scan line, and a first electrode coupled to a first node; a storage capacitor coupled between the first node and a second node; a third NMOS transistor including a gate electrode coupled to a second scan line, and a first electrode coupled to a data line; a second NMOS transistor including a first electrode coupled to a second electrode of the third NMOS transistor, and a gate electrode and a second electrode coupled to the first node; a fifth NMOS transistor including a gate electrode coupled to an emission control line, and a first electrode coupled to a first power source; an organic light emitting diode (OLED) comprising an anode coupled to the second node; and a first NMOS transistor for providing a driving current to the OLED.