A mother substrate unit organic light emitting display in which grooves are formed on the internal surface where a scribing line is formed to scribe a mother substrate on which a plurality of display panels are formed into unit display panels so that a scribing process is easily performed and a method of fabricating the same are disclosed. The mother substrate unit organic light emitting display includes a first substrate including a plurality of display panels and a scribing line defined between the display panels such that each display panel includes a pixel region in which an organic light emitting diode (OLED) including a first electrode, an organic layer, and a second electrode is formed and a non-pixel region, a second substrate that is arranged on the first substrate to overlap the first substrate and on which grooves are formed to correspond to the scribing line, and a plurality of frits provided between the first substrate and the second substrate and formed along the circumference of the pixel regions. The first substrate and the second substrate are attached to each other by the plurality of frits.