Polyethylene-clay hybrids have been prepared successfully by melt compounding with maleic anhydride grafted polyethylene (MA-g-PE). organophilic clay and polyethylene. In these polyethylene-clay hybrids, the silicate layers of the clay were exfoliated and dispersed to the monolayers. The hybrids exhibit higher tensile yield strengths and tensile moduli than those of polyethylene matrices and those of polyethylene-inorganic clay composites. When the 5-wt% clays were loaded, the tensile yield strength and the tensile modulus of the hybrid were. respectively, 1.4 and 1.8 times higher than those of the polyethylene/MA-g-PE mixture. The gas permeability of that clay hybrid decreased 30% compared with polyethylene/MA-g-PE mixture.