Abstract: We obtained a cDNA sequence that encoding a putative peptidoglycan recognition protein (PGRP) of American lobster, Homarus americanus, by in silicon cloning in this study; and analyzed the deduced protein by bioinformatics methods in terms of its general physical and chemical properties, hydrophobicity, signal peptide, secondary / tertiary structure and localization sites in cells. The results show that the obtained 920 bp long cDNA contains an open reading frame (834 bp) which encoding a protein with 277 amino acids. The protein has a signal peptide in its N terminal, a PGRP domain in its C terminal, which means that the protein maybe is a secretory protein, short type PGRP. Phylogeny analysis indicates that the protein is more like the PGRP-SC2 and PGRP-SD in Drosophila melanogaster.