Over the last three decades, welfare states across the West have embraced a host of new technologies and initiatives in the name of fighting welfare abuse and fraud (see Cook 1989, 2006; Wacquant 2001, 2009). Increasingly, these practices of 'welfare policing' are graduated according to risk; particular welfare populations considered at greater risk of welfare fraud are subject to more intense scrutiny. Drawing on interview research with compliance staff from the Australian Department of Human Services, this paper critically explores how the rationality of risk figures in the process of welfare surveillance in Australia. It pays particular attention to the ways in which risk formulations are embedded in gender and class politics, and how this has led to the characterisation of single mothers and unemployed recipients as more 'risky' than the general welfare population, a point that is often overlooked in the literature. But, far from being immutable, this paper also considers how the politics of risk are open to reformulation with often unexpected results.