The aim of this work was to carry out a spectroscopic (FTIR) and calorimetric (DSC) study of water adsorption and desorption processes for chitosan (CH) and its blends with hydroxypropylcellulose (HPC). The amount of water adsorbed by samples was obtained from gravimetric measurements and sorption isotherms were prepared. Through the analysis of adsorption/desorption heats, states of water in films were identified.