Culex gelidus has a wide distribution throughout Asia, where it is a vector of Japanese encephalitis. It was first detected in Australia in 1999, with archived material revealing an introduction sometime prior to 1994. It is currently widely distributed throughout northern and particularly north-eastern Australia. Using climate matching software (CLIMEX Version 1.1) and the known distribution of Cx. gelidus throughout Asia, a predicted distribution for Australasia based on current climate was developed. A potentially wide distribution throughout coastal Australia, particularly in tropical and subtropical areas, was revealed. Few inland locations were suitable, except in tropical areas of the Northern Territory and Queensland. The predicted distribution presented here is concordant with most recent collection records of Cx. gelidus in Australasia. However, there are a small number of exceptions which highlight some of the limitations of this approach for predicting mosquito distributions. The presence of Cx. gelidus in a large artificial swamp in Alice Springs is one such example. The predicted Cx. gelidus distribution incorporates highly populated areas, in which people may experience an increased risk of mosquito-borne viral encephalitis should this mosquito spread throughout its entire predicted range.