In this study blend films of chitosan (CH) and hydroxypropyl guar gum (HGG) were prepared using a conventional Solvent-casting technique and were dried at room temperature. Their miscibility and other properties were studied by Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, scanning electron microscopy, differential thermal analysis, ultraviolet analysis, and tensile strength tests. The physical and thermal properties of the films depended on the blending ratio. The maximum tensile strength and breaking elongation values achieved were 58.94 MPa and 17.25%, respectively, with a 60%, content of HGG. Thermal stability also was improved, and the blend film containing 60%, HGG had greater thermal stability than did the other blend and pure CH films. In addition, the best optical transparence was observed from 500 to 800 nm in the blend film containing 60% HGG. The results indicate that intermolecular interactions that resulted from hydrogen bonding between CH and HGG occurred in the blend films. (C) 2003 Wiley Periodicals, Inc.