Many exotic vertebrate species have been introduced either accidentally or intentionally into the Australian environment. Native species have also become pests due to changes in landscape use. Management of these pest populations, whether introduced or indigenous, is of concern both nationally and internationally. Public approval of existing pest control techniques involving lethal agents (poisoning, shooting, trapping, or disease) has declined in favour of alternative techniques, which are more humane, cost effective, species-specific, environmentally friendly, and suitable for delivery on a continental scale. Population management through disruption of reproduction rather than through the use of mortality agents has gained acceptance in the past 10-15 years. This has led to considerable research into the development of immunocontraceptive agents, for example to prevent mouse populations irrupting to plague proportions in cereal-growing regions of Australia. We have examined whether mouse populations can be managed with fertility control delivered using a transmissible mouse-specific virus (mouse cytomegalovirus, MCMV), engineered to carry an infertility agent. Field and laboratory results, as well as computer modelling, show excellent prospects for the use of vaccines based on MCMV. However, the efficiency of transmission of infertility remains a major challenge for the current research program. The public acceptability of the technology is yet to be confirmed. The issues of species specificity, delivery system stability, transmission efficiency, and other potential or perceived risks require open and wide-ranging debate, nationally and internationally, before trial field experiments of a genetically modified virus for controlling field populations of mammals could occur.