This study aims to determine the microcrystalline cellulose characteristics of seaweed Eucheuma cottonii. The reserach was conducted by using experimental method, that was extracting the seaweed Eucheuma cottonii by hydrolysis it in extractor HCl solution for varied concentration (2, 2,5 and 3N) to produce microcrystalline cellulose.The results showed that the seaweed skin was containing of 3,4…