Molluscs constitute the second largest animal phylum, after Arthropods, in terms of number of species. Molluscs are widely distributed throught the world and have many representatives such as slugs, whelks, clams, mussels, gastropods, oysters, scallops, squids and octopods etc. in marine and estuarine ecosystem. The present study was carried out to screen the antimicrobial activity of haemoplymph of selected gastropod species. The antimicrobial activity of the haemolymph sample was carried out against seven human pathogens namely Bacillus subtilis, E.coli Klebsiella pneumonia, Pseudomonas aeruginosa, Salmonella typhi, Staphylococcus aureus and Streptococcus mutans. The maximum zone of inhibition was observed against Klebsilla pneumonia, Bacillus subtilis, Salmonella typhi (8mm) by the haemolymph collected from Nerita albicilla. The protein content of the haemolymph sample was estimated using Lowry’s method. Variation in protein content of the haemolymph among the gastropod species was observed.