An organic light-emitting diode (OLED) display and a method of manufacturing an OLED display are disclosed. In one aspect, the method includes forming a data electrode layer and patterning the data electrode layer so as to form a source electrode, a drain electrode, and a pad electrode. The method can also include forming a first organic insulating layer over the source, drain and pad electrodes and forming a via hole corresponding to the source electrode or the drain electrode in the first organic insulating layer via a one tone mask. The method can further include forming an OLED including an anode electrically connected to the source electrode or the drain electrode, an organic emission layer, and a cathode, and etching a first portion of the first organic insulating layer formed over the pad electrode and a second portion of the organic emission layer formed over the pad electrode.