Cash transfers – direct cash payments to individuals and 
households, often targeting the poor and vulnerable – have increasingly become a cornerstone of many low- and middle-income countries’ social protection strategies. Cash transfers help reduce poverty and can reduce economic and gender inequalities, as well as exclusion, all of which are priority outcomes in UNDP’s Strategic Plan: 2014-2017. An investment approach has recently become central to AIDS responses. In a joint paper in 2012, UNDP and UNAIDS describe the relevance of ‘development synergies’ – investments in other sectors that can have positive impacts on HIV outcomes – to strategic investments in AIDS responses. Social protection is an example of a development synergy, and a growing evidence base indicates that cash transfers in particular have the potential to prevent HIV, especially sexual transmission of HIV, in certain contexts.This paper presents and analyses the evidence on cash transfers and HIV prevention, which demonstrates impacts across three broad, related areas: Cash transfers can address structural drivers of HIV, such as economic and gender inequalities and low levels of education; Cash transfers can increase uptake of critical prevention services, such as voluntary counselling and testing, with implied impacts on HIV; and Cash transfers tied to proxies for risk of HIV infection have shown promising, though mixed, results.