cDNA encoding Lateolabrax japonica interleukin-8 (LjIL-8) open reading frame (ORF) was cloned by RT-PCR. Sequencing results showed that the LjIL-8 ORF nucleotide sequence was 300 bp in length, encoding a prepropeptide of 99 amino acids. The deduced mature amino acid sequence of LjIL-8 was compared with those of several fish and mammalian species. The results showed that the LjIL-8 had 23%-48% and 25%-92% identities with mammalian and fish IL-8s in deduced amino acid sequence. Phylogenetic analysis showed that the LjIL-8 had close relationship with Dicentrarchus labrax IL-8. Recombinant expression plasmid of pET-28a (+) was constructed by inserting the LjIL-8 ORF sequence into the prokaryotic expression vector pET-28a (+) . An expected protein band was observed on SDS-PAGE gel, recognized by monoclonal antibody against 6×His in Western-blotting assay.