The HIV treatment cascade has been a powerful illustrative tool used to explore the performance of HIV treatment programs. The cascade steps through the recruitment of HIV-infected individuals into treatment programs and the effectiveness of those programs, and despite its conceptual flaws provides an intuitively appealing snapshot of performance. Because of its advocacy potential attempts have been made to generate a prevention cascade, covering those HIV positive and negative or to integrate prevention into the treatment cascade generating a ‘prevention, treatment and care cascade’. However, these tend to diminish the focus on prevention, confuse different interventions and do not provide a simple scheme through which to measure performance. Here we explore the required elements for prevention cascades for HIV and other sexually transmitted infections and identify the steps linking the delivery of interventions with their use in populations. Starting from the susceptible population at risk we can consider whether the intervention is available to them, whether they uptake the intervention, whether they adhere to the intervention and what the efficacy of the intervention is. Cascades for the delivery, use and effectiveness of prevention products should be able to identify who has been protected, what the key failures in protection are and the relative importance of system and product characteristics. In explaining theoretically how we might think about prevention programs we hope that empirical studies will consider adopting this framework, which has guided some thinking about voluntary medical male circumcision programs and HIV pre-exposure prophylaxis programs. In HIV treatment global targets and indicators have been set based on the treatment cascade and without similar targets for other prevention interventions they are likely to be neglected.