The pathogenic microorganisms are exceptionally adept to acquiring resistance to antibiotic and antiseptic drugs, so new strategies are there for needed to deal with this threat. Antimicrobial peptides from a wide spectrum of insects possess potent microbicidal properties against disease-related microorganisms. This study investigated the antimicrobial activity of maggot hemolymph from Sarcophaga argyrostama, a common species of flesh flies in Egypt. The crude hemolymph of the third instar larvae was tested against selected pathogenic strains of Gram positive bacteria, Streptococcus pyogenes, Staphylococcus aureus, S. epidermidis, Bacillus subtilis and Micrococcus lutea; Gram negative bacteria, Pseudomonas aeruginosa, Proteous vulgaris, Salmonella typhimurium, Klebsiella pneumo-niae and Escherichia coli and Fungi, Aspergillus niger, Syncephalastrum racemosum, Geotrichum candidum, Candida albicans, Microsporum canis and Trichophyton mentagro-phytes. The results showed that hemolymph was more effective against Gram positive bacteria especially Bacillus subtilis and effective against the filamentous fungus Geotrichum candidum. The most affected bacterial
and fungal species were examined by TEM to study the antimicrobial peptides action in the hemolymph. Also, crude hemolymph was subjected to SDS-PAGE to estimate the proteins number and molecular weight.