Most minerals in the Filipino diet are derived from vegetables and certain fishery products. This is true particularly with the majority of low-income families who subsist mainly on rice and dried fish and sometimes on seaweeds and shellfish. Com¬mon examples of shellfish found in certain localities in the Philippines are shrimps, crabs, oysters, tulya (Corhicula marti- lensis Philippi), and paros (Soletellina elongata Lamarck). The local markets in the Manila Bay area are sufficiently supplied with these products at certain times of the year. In general, they cost less than other food materials. In view of their easy availability in the market and considering their low cost com¬pared to other foods, this experiment was planned to determine the part they play in the nutrition of the average citizen with reference to calcium availability. Among the mineral elements, calcium needs more attention in considering food value and food supplies from the viewpoint of meeting nutritional needs as it makes up a large proportion of the bones which compose the structural framework of the body.