Ribonuclease III gene of infectious spleen and kidney necrosis virus( ISKNV) of Siniperca chuatsi had been sequenced. The open reading frame of the gene is 771 nucleot ides long, encoding a putative protein of 256 amino acids w ith 28. 9 kD. The 5. and 3. noncoding regions have TATA boxes. A palindrome is contained downstream of the translation stop codon. Compared w ith the RNase IIIs found in ISKNV and other species, the higher homology among ISKNV and the two iridovirus is present, and ISKNV has lower identity with other species, especially yeast and rhabditida.