Given the growing awareness of environmental issues related to the use of traditional plastics, scientific research in recent years has focused on the study of new sustainable materials able to compete with petroleum-based polymers. Petrochemicals are widely used by the packaging industry, which is one of the main responsible for plastics production in Europe. ComBIOsites project, in the frame of the MSCA programme of the EU, aims at developing recyclable composite materials for packaging application. As part of this project, the present work deals with the study of the barrier properties of a biobased polymer reinforced with cellulosic fillers. Due to its abundance in several natural sources, cellulose is a promising candidate for producing new biobased polymers.