This is the first report of an epicaridean isopod infecting cephalopods. Three cryptoniscus larvae (Isopoda, Epicaridea) were recognized externally and found entirely embedded in the oral bulb at the beginning of the esophagus of two female Patagonian squid (Loligo gahi) sampled in North Peruvian and South Chilean waters, respectively. There was an extremely low prevalence (< 2%) and mean intensity (one) of infection which we believe indicated an accidental infection. However, the tissue location indicated successful penetration and colonization of the squid host.