A conductive organic/inorganic complex composition, a method of preparing the composition, a thin conductive organic/inorganic complex film prepared using the composition, an organic electroluminescent device comprising the thin conductive organic/inorganic complex film, and a method of manufacturing the organic electroluminescent device. The conductive organic/inorganic complex composition is prepared by mixing a mixed solution comprising a conductive polymeric monomer, an oxidizing agent, and an alcohol solvent with a silica sol solution comprising an organosilicon compound, water, an acid catalyst, and an alcohol solvent. According to the present invention, the conductive organic/inorganic complex composition is hydrophobic and insoluble in water and an organic solvent, has a high mechanical strength, and is thermally and chemically stable. Further, a compositional composition of the conductive organic/inorganic complex composition can be changed over a wide range.