In a laser irradiation device, a patterning method and a method of fabricating an Organic Light Emitting Display (OLED) using the same. The laser irradiation device includes a light source, a mask, a projection lens, and a Fresnel lens formed at a predetermined portion of the mask to change an optical path. When an organic layer pattern is formed using the laser irradiation device, laser radiation is irradiated onto a region of an organic layer, which is to be cut, and the laser radiation is appropriately irradiated onto a region of the organic layer, which is to be separated from a donor substrate. The laser radiation irradiated onto an edge of the organic layer pattern has a laser energy density greater than that of the laser radiation irradiated onto other portions of the organic layer pattern. As a result, it is possible to form a uniform organic layer pattern and reduce damage of the organic layer.