A method of inspecting the quality of an organic light-emitting diode (OLED) and an inspecting system for performing the method are disclosed. In one aspect, the method includes applying an input voltage to the OLED, measuring an OLED voltage across the OLED and an OLED current flowing through the OLED, estimating a parameter of the OLED based at least in part on the OLED voltage and the OLED current, and extracting a physical characteristic of the OLED based at least in part on the parameter.