A method of manufacturing a display device including the steps of: forming, on a first mother substrate, pixels including pixel electrodes, gate lines and data lines connected to the pixels; dividing the data lines into groups and connecting the data lines of the same group to one connection line; forming inspection electrodes on the first mother substrate overlapping a shot boundary portion of a mask, the inspection electrodes connected to a plurality of connection lines, respectively; preparing a second mother substrate; forming a common electrode on the second mother substrate; forming a mother panel including the first and second mother substrates and a liquid crystal layer therebetween; applying a first voltage to the common electrode and a second voltage to the inspection electrodes; and determining whether the inspection electrodes and the common electrode are short-circuited based on an image displayed in a display area of the mother panel.