Blend films consisting of chitosan andhydroxypropyl methylcellulose (HPMC) were prepared froma solvent casting technique at room temperature.Mechanical properties and physical properties wereinvestigated. It was stablished that chitosan had morecrystallinity than HPMC. Crystallinity and tensilestrength of blend films decreased with an increase inHPMC content while elongation increased.However, waterabsorption and solubility in different aqueous media ofblend films depending on pH of solution.Waterabsorption of blend films increased with an increase inprotonated amino group in chitosan molecules. Heattreatment did not change tensile strength andelongation but reduced water absorption and solubilityof blend films having chitosan content from 50 to 100 %in a medium of pH 1.0 and pH 6.1. On the other hand,water absorption and solubility in a medium of pH 7.4did not change. Heat treatment might be attributed tothe formation of crosslinks and/or crystallites in theblend films.