In the present study, attempt has been made to assess the antimicrobial activity of haemolymph collected from a freshwater crab Maydelliathelphusa masoniana. The hemolymph collected was subjected to antimicrobial activities against clinical pathogens. Six bacterial species namely Escherichia coli, Streptococcus pyrogenes Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis. and Salmonella paratyphi. The antibacterial response of hemolymph found to vary with respect to sex. In male, the highest zone of inhibition was observed against E.coli while lowest in case of Bacillus subtilis whereas in female, the highest zone of inhibition was observed against Streptococcus pyogenes and the minimum in case of Bacillus subtilis.