Previously existing sources of data regarding mosquitoes in inland areas of south-west Western Australia are few and qualitative in nature. This is the first attempt to quantitatively investigate mosquito fauna in this region. The existing data are reviewed and compared with the results of the quantitative surveys presented in this paper. Temporal comparisons appear to indicate that mosquito community structure in the region may have changed since the initial surveys in the 1950s from a combination of freshwater-breeding species towards a strong dominance of Aedes camptorhynchus (Thomson), a major vector of Ross River virus in southern Australia. It is speculated that this shift may have been brought about by the increasing area and severity of dryland salinity in the region over the last century, and also may increase the potential for Ross River virus disease transmission.