Many Aedes aegypti eradication and control campaigns are faced with administrative, financial, and technical constraints. At the same time Ae. aegypti appears to be extending its geographical distribution and utilizing an increasing number of different larval habitats. Countries such as Brazil, Bolivia and Paraguay have had Ae. aegypti reinfestations. Jungle yellow fever has spread into areas closely adjoining urbanizations infested with Ae. aegypti and the potential for urban yellow fever remains great. Since 1965 jungle yellow fever have been reported in 12 countries with 228 cases occurring in 1981. All 4 serotypes of dengue occur in the Americas with a major pandemic of dengue serotype 1 beginning in 1977. In 1981 dengue serotype 4 was identified in the Caribbean and it has spread to at least 13 countries. Dengue haemorrhagic fever appeared in Cuba in 1981 with 344,203 cases and 158 deaths. The etiological agent has been identified as dengue serotype 2. The control measures are described.