An organic light emitting display device and a driving method thereof may turn on first and second transistors, wherein the first transistor electrically connects a data line and a first node of a driving transistor that drives an organic light emitting diode of each sub-pixel, and the second transistor electrically connects a second node of the driving transistor and a reference voltage line, and may provide a detection driving data voltage and a detection driving reference voltage to the first and second nodes of the driving transistor, respectively, to perform initialization; may turn off the first and second transistors to float the first and second nodes of the driving transistor, and may detect one or more from among a short and to an open of the organic light emitting diode by sensing the voltage of the first node or the second node of the driving transistor.