In this study synthesis and characterization of biopolymer/clay biocomposites was aimed using naturally occurring polysaccharide (xylan) as biopolymer and montmorillonite type clay (NaMt). Xylan was extracted from corn cobs via alkaline oxidative treatment. Maximum solubility of xylan was determined as 1% (w/v) in water at room temperature. Thus synthesis was realized following two routes: first NaMt concentration was kept constant at 2.0 x 10(-2) g/ml and xylan concentration was changed. Latter xylan concentration was kept constant at 1.0 x 10(-2) g/ml and NaMt concentration was changed. Natural xylan, NaMt and biocomposites were examined in terms of their spectral, electrokinetic, rheologic, morphologic and thermal properties. Results showed that lower amounts of xylan interacted with NaMt on the surface, however, when the xylan amount was increased also intercalation of NaMt has occurred. Biocomposites showed better thermal and rheologic behaviors with respect to the starting materials. (C) 2008 Elsevier Ltd. All rights reserved.