In daily life, the use of plastic is widespread, causing serious problems with plastic waste. Moreover, as the population continues to grow, the amount of waste will also increase. Therefore, immediate action is to switch from plastic made from petroleum, which is difficult to decompose, to plastic made from biodegradable materials. In this study, biodegradable plastic was made from rubberized cassava starch and tofu dregs with the addition of sorbitol as a plasticizer. This research aimed to determine the effect of the plasticizer composition of sorbitol, rubber cassava starch, and tofu dregs starch for making biodegradable plastics and to determine the characteristics of the plastic products.The production of biodegradable plastic using rubber cassava starch and tofu dregs starch added with sorbitol as a plasticizer was divided intothree stages, namely producing flour from rubberizedcassava starch and tofu dregs starch, making biodegradable plastic and analyzing biodegradable plastic samples. The best results from various sample analyses were a tensile strength value of 4291.9 kPa, an elongation percentage of 35%, a water absorption capacity of 41.94%, and a biodegradation test of ± 2 weeks had decomposed around 80% in the soil.