Dengue haemorrhagic fever (a viral disease transmitted by mosquitoes) is of increasing concern in South-east Asia, particularly Vietnam, Laos, Cambodia, Myanmar and Thailand. It is a re-emerging disease, with several recent outbreaks and with increasing vector resistance to insecticides. Civil conflict in this region, coupled with the breakdown of health structures, major ecological disturbances, population movements, rampant urbanisation have all contributed to an increased incidence of the disease and an alarming rise in case-fatality rates. Although the disease has clearly changed in the last decade, little is commonly known of the recent epidemiological profile of the disease. On-going research and epidemiological information is not available on a regional basis. An analysis and inventory of existing knowledge/regional resources is essential for health planning, vaccine trials and regional control strategies.