Dengue fever is a viral disease carried by mosquitoes in the tropics and sub-tropics. Yellow fever is a serious viral illness spread by day-biting mosquitoes. It occurs only in sub-Saharan Africa, Panama, Trinidad and parts of South America. Both diseases have had a high-profile in the last several years and more conferences dedicated to these viruses have been emerging in the last two years. Topics will include basic research in: Dengue ecosystems, immunology, Epidemiology, Dengue genetics, physiopathology, research priorities, vaccines, vector biology and ecology, new knowledge of vaccines, yellow fever and other arboviruses.