An organic electroluminescent display device and a method of producing the same are provided. The organic electroluminescent display device includes: a substrate; and an organic electroluminescent unit formed on a surface of the substrate and including a first electrode, an organic layer and a second electrode sequentially deposited on the substrate, in which the organic electroluminescent display device includes a diffraction grating layer having low refractive gratings and high refractive gratings alternately formed parallel to the substrate, and a high refractive layer formed on the diffraction grating layer interposed between the substrate and the first electrode. According to the organic electroluminescent display device, the light coupling efficiency can be increased due to minimized voids and unevenness generated in the formation of a diffraction grating layer, optical losses due to a first electrode can be prevented due to a high refractive layer interposed between the diffraction grating layer and the first electrode to focus light distribution on the high refractive layer, and the light coupling efficiency can be maximized due to increased light distribution in the diffraction grating layer.