This study was aimed to apply the powder of sea cucumber (Holothuria scabra) in the formulation of composite sago based biscuits. The sea cucumber was processed through smoking, drying, and grinding to make a powder. Biscuits were made by mixing that powder with other ingredients. The formulations of the biscuits dough applied were T0 (100% wheat) as a control, T1 (50% wheat, 40% sago, 10% sea cucumber), T2 (50% wheat, 35% sago, 15% sea cucumber), T3 (50% wheat, 30% sago, 20% sea cucumber), and T4 (50% wheat, 25% sago, 25% sea cucumber). The product obtained was then measured its sensory properties and antioxidant activity. Other characteristics tested were their chemical content, and morphological properties with Scanning Electron Microscope (SEM). The results showed that the formulation of T1 gave a relatively best sensory characteristic. Meanwhile, protein, fat, minerals, and antioxidant activity were increased as the percentage of sea cucumber powder substitution was increased. The morphological appearance of the products indicated that sea cucumber powder was evenly mixed with other ingredients in the formulation. The inclusion of sea cucumber in the formulation of processed food products had improved the nutritional and functional values of the food, and it may improve its added value.