ObjectiveTo record the human cases of dengue fever (DF) and investigate the Aedes mosquito species circulating during the Hanoi 2011 DF epidemics.Methods24 different outbreak points were recorded in 8 districts between August and December 2011.Results140 patients were hospitalized following dengue diagnostic with a predominance of males (59.3%) and the 15–34 age class. Only DENV-1 (11.27%) and DENV-2 (88.73%) serotypes were detected in human samples. Mosquito sampling performed in and around patients households revealed the predominance of Aedes aegypti (A. aegypti) (95.15%) versus Aedes albopictus (4.85%).ConclusionsThere is a positive correlation between the population density of A. aegypti and the number of human cases and duration of outbreaks. This was not observed for Aedes albopictus. Three pools of A. aegypti were positive with dengue virus, two with DENV-1 and one with DENV-2.