The rapidly increasing burden of dengue, the varied and often poorly understood factors contributing to its global spread, and the challenges of preventing and controlling it have led to a renewed call for more research and training on the disease. The main aims are to improve vector control, case management, and primary prevention through vaccine development. The World Health Organization (WHO), through its inter-departmental working group on dengue, is actively engaged in supporting and co-ordinating the major research activities. The dengue research initiatives of the Special Programme for Research and Training in Tropical Diseases (TDR), other departments at the WHO's Geneva headquarters, the WHO's regional and country offices, and the organization's dengue-affected member states are summarized in this article. This intensified effort, in close collaboration with other stakeholders, is contributing towards the goals of reversing the current epidemiological trends and of reducing the global burden posed by dengue in all of its forms.