The nanocomposites of poly(ethylene-co-vinyl alcohol) (EVOH) with organoclay were prepared by a solution-precipitation method. The structures of nanocomposites were examined by X-ray diffraction. The exfoliation of organoclay was more evident in the nanocomposites of the EVOH containing 18 mol% vinyl alcohol (EVOH18), compared to the EVOH containing 5 mol% vinyl alcohol (EVOH5). Some of the bilayer alkylammonium structures at the clay gallery changed to monolayer structures in the nanocomposites. The thermal properties measured by differential scanning calorimetry showed the organoclay enhanced the crystallization of EVOH, however, it retarded crystallization when there was too much. The modulus of EVOH18 showed about a 2-fold increase of pristine polymer when using 7% of reinforcing organoclay. (c) 2005 Springer Science + Business Media, Inc.