An organic light-emitting diode (OLED) display and a manufacturing method thereof are disclosed. One inventive aspect includes a first substrate, a second substrate, and a first insulation layer, a metal layer and a second insulation layer formed on the first insulation layer. The metal layer is formed on the first insulating layer and has a first through hole and is formed of the same material as a data line applying a data signal to the display area. The second insulation layer is formed on the metal layer and has a second through hole. The inventive aspect further includes a sealing member formed by filling the first and second through hole so as to seal the first substrate to the second substrate.