The ecology of mosquito populations in relation to weather conditions, emergent plants and predation in an urban wetland of Canberra was studied. Anopheles annulipes, Aedes notoscriptus, Aedes australicus, Aedes alboannulata, Culex annulirostris and Culex quinquefasciatus were found. Temperature was a major climatic factor in determining the abundance of mosquito populations in the wetland. First collections and subsequent development of mosquitoes in Ginninderra wetland are likely to depend on local weather conditions each year. The wetland proper was not a suitable habitat for mosquito breeding. Tall emergent vegetation may have obstructed oviposition and predation was also important in limiting colonization by mosquitoes. Instead, isolated temporary waterbodies which were free of predators, such as ground depressions, tyre tracks, domestic waste containers, were the most important habitats for mosquitoes adjacent to the Ginninderra wetland. Field experiments found that predation of mosquito larvae by mosquitofish Gambusia qffinis and notonectids Anisops was more efficient in sunlight than shade and this was affected by the height of emergent plants.