Antimicrobial peptides (AMPs)， the natural antibiotics bestowed upon all forms of life， consist of small molecular weight proteins with a broad spectrum antimicrobial activity against a variety of pathogenic microorganisms. Piscidins are one of the AMP families that are imperative for the innate defence mechanisms of teleosts. Atlantic cod， a basal fish belonging to the superorder Paracanthopterygii also possesses multiple piscidin peptides. Two piscidin paralogues (pis1 and pis2) and a novel alternative splice variant of pis2 of this fish were previously described by us. To shed light on other potent roles of these molecules， now we have mapped the distribution of piscidin 1 (Pis1)， in different tissues and organs of cod through immunohistochemistry (IHC) employing an affinity purified polyclonal antibody specific to Pis1.