Nanostructure of poly(ethylene-co-vinyl acetate)/organically modified montmorillonite (MMT; EVA/organoclay) nanocomposites prepared by melt intercalation process was investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Three kinds of organoclays were used to see their influences on the nanostructure of the EVA hybrids. The effects of the polar interactions between the polymer and the silicate layers of organoclays were also investigated by grafting maleic anhydride onto EVA. It was found that the strong polar interactions between the polymer and the silicate layers of organoclays are critical to the formation of polymer-layered silicate nanocomposites. The results also showed that increasing the mixing temperature was unfavorable to improve the dispersion of organoclays in the EVA matrix. (C) 2003 Wiley Periodicals, Inc.