the determination of moisture sorption isotherms is a way of characterizing the sorption capacity of the film [5] and [6]. Although the prediction of water transport through hydrophilic films like chitosan films is complex, the determination of sorption isotherms is of considerable interest for industry since it provides information for processes like drying, storage and transport, which affect the quality of the film. To our knowledge, there is no data available about the effect of the molecular weight of chitosan and the effect of the glycerol used to improve the flexibility of chitosan films on moisture sorption properties. In this context, the aim of this work was to prepare chitosan films and obtain reliable data for moisture sorption behaviour in order to provide novel and useful information for the design and processing of chitosan films