The increase in styrofoam waste can cause environmental pollution, therefore efforts are required to reduce the use of styrofoam. One of them is by replacing it with biofoam made from agricultural industry waste such as bagasse because if this garbage is not used, it may cause environmental issues. Bagasse has a potential to be utilized as biofoam. This research aims to extract cellulose from bagasse through delignification and bleaching processes, as well as synthesize and characterize biofoam using cellulose from bagasse with the addition of chitosan variations of 2, 3.5, 5, and 6.5 g. The stages of this research are the extraction of cellulose from bagasse waste with FTIR and XRD analysis, making biofoam and biofoam characterization tests. The results of cellulose extraction from bagasse are O-H, C-H and C-O functional groups that indicate the presence of cellulose. In XRD analysis, the cellulose sample has a crystallinity index of 70.74%. Biofoam based on sugarcane bagasse cellulose with the addition of 2 g chitosan has the best characterization, which has a density of 1.23 g/mL, with a water absorption value of 46.03% at 24 hours immersion and biodegradability of 20.68% for 28 days.