Red imported fire ants (Solenopsis invicta) (Hymenoptera: Formicidae) are a relatively new arrival to Australia. Currently a concerted eradication program is in place that aims to eradicate them by 2006. If red imported fire ants are not eradicated, they are likely to spread to many parts of the Australian continent. There can be no doubt that S. invicta will pose a substantial risk to Australia’s fauna if it spreads beyond its current Australian range and is not eradicated. If the worst-case scenario occurs and their range increases to cover most of the continent as predicted, wide-ranging species declines in a variety habitats are to be expected. Although endangered species are of particular concern, many common Australian animal species have experienced range declines, and the additional pressure caused by S. invicta may be sufficient to result in a new wave of species losses. It is crucial that we determine which groups have already been negatively affected by fire ants in Australia and that we establish which fauna is most at risk to ensure any future research and conservation funding is applied appropriately.