The present invention provides an organic electroluminescent display device and a method of preparing the same. The organic electroluminescent display device may include a first electrode formed on a substrate. A second electrode may be formed so as to be insulated from the first electrode. One or more organic layers may be interposed between the first electrode and the second electrode and include at least an emission layer. One layer or a plurality of layers may be formed on the second electrode and comprise a material or materials having a refractive index higher than a refractive index used to form a material that comprise the second electrode. An organic electroluminescent display device fabricated in this matter has improved efficiency of light extraction. Such a device also resists infiltration of moisture and oxygen to a luminous part of the device that includes the first electrode, the second electrode, and the organic layer.