An organic electroluminescent (EL) display device and a method of manufacturing the same are provided. The organic electroluminescent display device includes a rear substrate, a organic EL portion formed on one surface of the rear substrate with a first electrode, an organic layer and a second electrode sequentially laminated. The front substrate is coupled to the rear substrate to seal an internal space in which the organic EL portion is accommodated, for isolating the organic EL portion from the outside. The front substrate further has a transparent moisture-absorbing layer coated on its internal surface.