The preparation and properties of poly(4-methyl-1-pentene) (PMP)/clay nano-composites are described for the first time. The effect of clay modification and compatibilizer on the formation and properties of the nanocomposites is studied. Layered silicates modified with two types of quaternary ammonium salts are used. The X-ray diffraction results indicate intercalation of the polymer into the intergallery spacing of the clay. Thermogravimetric analysis shows a delay in the degradation process. Dynamic mechanical analysis shows an increase in the storage modulus for the nanocomposites. The use of compatibilizer containing maleic anhydride and acrylic ester groups is explored. (C) 2003 Wiley Periodicals, Inc.