The application of natural biopolymers such as polysaccharides for the fabrication of bio-based membranes has recently attracted attention for CO2 separation from gas mixtures. Here we review the types of natural polysaccharides that are used in membrane processes for CO2 separation. Various derivatives of polysaccharides including esters, ethers, silyls, amines have been synthesized and used in gas separation membranes as the main component of self-standing membranes, or in a blend with commercial polymers, or as a thin layer on the substrates. Nanoparticles of raw polysaccharides have been added to polymer matrices to form mixed matrix membranes with enhanced gas separation efficiency. The effect of the functionalization of polysaccharides on CO2 separation performance is detailed.