An emerging disease known as acute hepatopancreatic necrosis syndrome has caused significant losses amongst shrimp farmers in China and Vietnam (2010), Malaysia (2011) and Thailand (2012). The disease affects both Penaeus monodon and P. vannamei. An emergency consultation was convened in Bangkok, 9-10 August 2012, to share information on this emerging disease, its occurrence, pathology and diagnosis, and to develop a coordinated regional response to the issue.