Taura syndrome disease, caused by Taura syndrome virus (TSV), is one of the most important viral diseases of penaeid shrimp in the Western Hemisphere resulting in catastrophic disease epidemics in farmed shrimp. We have cloned and sequenced a 3278 bp cDNA representing the 3' end of the TSV genome. Sequence analyses revealed that frame + 2 had the longest open reading (ORF) frame. This frame contained a 5'-terminal 19 non-coding bases followed by an ORF from nucleotides 20 to 3053 (encoding 1011 amino acids, aa) and a 3' untranslated region of 225 nts. The deduced aa sequence of TSV showed significant similarities with those of the coat proteins of insect picornaviruses, Rhopalosiphum padi virus, Plautia stali intestine virus, Drosophila C virus, Triatoma virus of Triatoma infestans and Himetobi P virus of brown plant hopper. A single transcript of approximately 10 kb was detected by Northern blot hybridization suggesting that the TSV coat protein gene is not expressed as a subgenomic RNA. We concluded that the genome organization of TSV is similar to insect picornaviruses. This is the first molecular evidence of occurrence of a picornavirus in the class Decapoda.