Although it is very important in view of public health to understand the mosquito breeding sites and key reservoirs existing around residential areas, such information is lacking in temporary housing sites constructed after the serious tsunami strikes on 26 December 2004 in Sri Lanka. This study clarified the situation regarding mosquito breeding 14 months after the tsunami in Sri Lanka by surveying temporary housing and non-damaged village areas, and also by examining people‘s knowledge related to mosquito breeding sites and mosquito-borne diseases. The relative frequency of mosquito larvae in wastewater pools was significantly higher in temporary housing than in village areas. The prevalence of storage containers at temporary housing and village areas was not significantly different. It was found that wastewater pools in temporary housing sites were the main breeding site of Culex quinquefasciatus Say, Cx. tritaeniorhynchus Giles, and Aedes albopictus Skuse whereas storage containers in village areas were the main breeding site of Cx. quinquefasciatus and Ae. albopictus. No mosquitoes bred in storage containers in the temporary housing but some Ae. albopictus did so in village areas. The questionnaires indicated a significant difference between residents of temporary housing and villages in response to the question: Do you know where mosquitoes breed? The proportion of the “wastewater pools” response was higher among temporary housing residents than among village residents. This knowledge among temporary housing residents may relate to the fact that wastewater pools are latent breeding sites for mosquitoes in temporary housing sites. Although residents in the temporary housing sites put salt and abluent into storage containers to prevent mosquitoes from breeding, wastewater pools receiving a constant supply of wastewater provided the best breeding site for mosquitoes.