The bacterium, Vibrio parahaemolyticus was isolated from 776 patients at Hat Yai Hospital in Southern Thailand from 2006 to 2010. 51.3–73.6% of the isolates were tdh+ trh− and Group-specific PCR positive pandemic strains. A comparison of the number of V. parahaemolyticus isolates in this study and that from the same hospital in 2000–2005 indicates that this region of Thailand is endemic for V. parahaemolyticus.