Technical Abstract: Abstract Tetraspanins, a large cell surface protein superfamily characterized by having four transmembrane domains, play many critical roles in physiological and pathological processes. In this study, we report the identification, characterization and phylogenetic analysis of the channel catfish tetraspanin 3 and tetraspanin 7 (CD231) transcripts. The full-length nucleotide sequences of tetraspanin 3 and tetraspanin 7 cDNA have 1453 and 1842 base pairs, respectively. Analysis of the nucleotide sequences reveals that each has one open reading frame, which appears to encode 241 amino acids with calculated molecular mass of 26.8 kDa and 251 amino acids with calculated molecular mass of 27.9 kDa for tetraspanin 3 and tetraspanin 7, respectively. By comparison with the human counterparts, the channel catfish tetraspanin 3 and tetraspanin 7 peptides have four transmembrane domains, three intracellular domains and two (small and large) extracellular domains. In addition, several characteristic features critical for structure and functions in mammalian tetraspanins are also conserved in channel catfish tetraspanin 3 and tetraspanin 7. These results with our previous studies on other channel catfish tetraspanins provide important information for further investigating the roles of various tetraspanins in channel catfish infection with microorganisms.