In a flat panel display device and a method of manufacturing the same, the flat panel display device is manufactured by forming a display unit on a substrate, forming a hydrophobic barrier layer for preventing a material of an organic layer from flowing around the display unit, and forming a thin film sealing layer by alternately stacking an inorganic layer and the organic layer on the display unit. Accordingly, formation of an edge tail of the organic layer is prevented, thereby preventing penetration of external moisture.