A method for manufacturing an organic light emitting display device includes forming a substrate insulating film an upper surface, a lower surface, and at least one of two side surfaces of a substrate and forming an organic light emitting diode (OLED) on the substrate on which the substrate insulating film is formed. An organic light emitting display device includes a substrate having a first surface, a second surface opposite to the first surface, and side surfaces that extend between the first surface and the second surface, a substrate insulating film disposed on the first surface, the second surface, and at least one of the side surfaces of the substrate, and an OLED disposed on one of the first surface or the second surface of the substrate including the substrate insulating film.