For preparation of drug containing calcium various sources of calcium is used. Among them most important are calcium from the CaCO3 stones produced from the mining, calcium produced from the protozoan’s like Foraminifera shells, mollusk shells such as pearls, comes and Calcium produced from the corals. The quantity of the calcium that is produced from different sources is not one and same. Seashells are excreted from the outer surface of the animal called the mantle and are made up of mostly calcium carbonate. Calcium carbonate can take the form of two different minerals, Calcite is the stable form, whereas aragonite is metastable, over time, or when heated, it can ultimately transform into calcite. In the present study an attempt is made to study the range of concentration of calcium carbonate in the shells of various gastropods in the sea shore of Bay of Bengal near Ramayapatnam Village, Gudlur Mandal of Praksam district Andhra Pradesh, India . The percentage of ash content and calcium content was determined using EDTA titrimetrically. The data shows there is a significant variation in the ash and calcium content of different species of gastropod shells. The significance of the variations in calcium content and its implications are discussed.