Mortalities of white shrimp Litopenaeus vannamei juveniles exceeding 80% have occurred in Taiwan since late 1998. It has been determined that Taura syndrome virus (TSV) is responsible for the epizootic outbreaks. In order to clarify the origin of these epizootics, a 3288 base pair fragment that encodes a TSV coat protein was amplified by RT-PCR. Analysis showed that the Taiwan isolate had 97% and 98% identity to the sequences in Genebank originated from isolates obtained from Mexico and Hawaii, respectively, both in cDNA and deduced amino acid sequences. These results suggest that TSV that infected the white shrimp in Taiwan in late 1998 and early 1999 is similar to the Western hemisphere isolates. We conclude that the Taiwan isolate originated in the Western hemisphere. Urgent and strict quarantine is advised to prevent Taura syndrome dissemination to other areas in Asia.