The cell –free hemolymph and hemocytes isolated from body-fluid of marine gastropod Rapana rapiformis distributed in the shallow waters of Pondichery coast, were tested for their antibiotic potential against five common human bacterial pathogens viz. Klebsiella pneumonia, Staphylococcus aureus, Pseudomonas aeruginosa, Vibrio cholera and E.Coli. The sensitivity test thro Disc diffusion assay revealed that cell–free hemolymph of Rapana rapiformis exhibited higher level of inhibition even at MIC of 2.5ul against Vibrio cholera when compared to reference drug. A peptide molecule in haemolymph that showed higher inhibitory activity with the molecular mass of 35kDa, has been found by Sodium Dodecyl Sulphate Polyacrylamide gel electrophoresis. It could be of greater interest to isolate and characterize this protein which might be used commercially against existing antibiotic resistant strains such as MRSA in future.