Crab shell is one of marine by-products that contains high level of calcium and phosphorus.These minerals are important for bone and teeth. Utilization of crab shell that has been made into powder can reduce the waste and also increasing the calcium and phosphorus intake. Deproteinization is a process of boiling crab shell in alkaline solution to remove the protein. The decreasing protein content can lead to an increasing calcium and phosphorus content in the crab shell. The aim of this research was to determine the effect of deproteinization to produce higher level of calcium and phosphorus and to determine the fortification level of the crab shell powder in tortilla chips. Crab shell was boiled in two kinds of solution (water and NaOH 3.5%) to observe the effectiveness of alkaline solution in producing higher level of calcium and phosphorus. Crab shell powder boiled in water had calcium (281.60 mg/g db) and phosphorus (20.04 mg/g db). Other properties of the selected crab shell powder were moisture content (5.39%), ash (72.40%), protein (7.90%), yield (62.45%),bulk density (0.88g/ml), degree of whiteness (80.44%),and water absorption (105.71%).Tortilla chips were produced with the fortification of crab shell powder with various levels (0,5,10,15, and 20%). The best fortification level was 5%, which was chosen based on the scoring and hedonic tests.Calcium and phosphorus content of the best tortilla chips were 16.79mg/g db and 3.17mg/g db respectively