The Intergovernmental Panel on Climate Change (IPCC) reported that climate change plays an important role in the distribution of Dengue Fever/Dengue Haemorrhagic Fever (DF/DHF) in space and time. Located in the Southeast Asia, Vietnam - a tropical monsoon country, is also strongly influenced by climate change as the development of the disease is more and more complicated. The study forcused on the impact of weather factors on the spread of DF/ DHF in Hanoi in 1998-2009, in which focus on determining the relationship between four weather elements: temperature, rainfall, humidity and wind speed with the incidence of DF/DHF in this period. The results showed that, translated DF/DHF usually occurs in the period from June to November. This period was also the time recorded highest measurements of rainfall, temperature and humidity. Especially after the rainy months and have the highest temperature as July, August, there was a sharp increase of new cases of dengue fever in the follow months (months 9-11). Two outbreaks of DFIDHF were reported in 1998 and 2009 was also a period recorded the highest rainfall and temperatures in the 10 years in Hanoi. Results from the regression model explained 28.1 percent the changing of dengue cases was due to temperature, humidity and wind speed.