Annually, the Philippines produces around 25,000-35,000 metric tonnes of blue swimmer crabs (Portunus pelagicus). Consequently, significant amounts of crab waste are generated, leading to a variety of waste management problems. Highvalue materials chitin and chitosan can be extracted from the shells of crustaceans and have been the focus of research in various fields for their potential food industry, geoenvironmental, and materials engineering applications. This study examines chitosan biopolymer derived from crab shell waste using the chemical method of extraction. Chitin and chitosan were successfully synthesized from Portunus pelagicus shells using the chemical method of extraction with a percentage yield of 69.4% and 55.3%, respectively.