© 2009 University of Queensland and Blackwell Publishing Asia Pty Ltd.This article examines the implications of high levels of informal (or invalid) voting in Australian national elections using a social exclusion framework. The rate of the informal vote is an indicator of social and political exclusion with particular groups of Australians experiencing inordinate electoral disadvantage. Poorer voters, voters from non-English speaking backgrounds and those with low education levels are especially disadvantaged by factors peculiar to the Australian voting experience. We begin by exploring the character and pattern of informal voting and then canvass the technical and socio-economic factors which explain it. We conclude by considering propose...