The 20th Annual Latin American Symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 76th Annual Meeting in Lexington, KY, in March 2010. The principal objective, as for the previous 19 symposia, was to promote participation in the AMCA by vector control specialists, public health workers, and academicians from Latin America. This publication includes summaries of 40 presentations that were given orally in Spanish or presented as posters by participants from 5 countries in Latin America, the United Kingdom, and the USA. Topics addressed in the symposium included: surveillance, chemical and biological control, and insecticide resistance associated with Aedes aegypti; distribution, behavior, and control of Culex; bionomics, ecology, and chemical and biological control of Anopheles vectors of malaria; insecticide resistance; and studies of dengue, West Nile virus, and Triatoma.