Conditional Cash Transfer programmes (CCTs) have been at the core of the remarkable expansion of social protection in Latin America in the early twenty-first century. Our article reviews the origins of CCTs in the Social Investment (SI) approach to social policy design, explores their characteristics and traces their expansion in Latin America. It further questions whether CCTs designed under the influence of SI can generate long-term substantial improvements in social outcomes. Our analysis suggests that while CCTs have evidently produced a number of positive outputs they are not, on their own, enough to achieve the aim of reducing poverty. CCTs appear to be more effective in poverty alleviation when they are accompanied by – or form part of – a wider package of measures that enhance social and employment rights, integrating workers into the formal economy under better conditions. We conclude that unless the structural deficiencies that shape many of the Latin American welfare regimes are addressed, the potential of social investment policies, like CCTs, to combat poverty will remain limited.