This paper provides an overview of the political and economic context under which Mexico’s Progresa-Oportunidades was introduced to prelude the emergence of social assistance in Latin America. The paper identifies four distinctive features of the programme that were revolutionary in their own right. First, the Progresa-Oportunidades embraced a multidimensional approach to poverty, linking income transfers with simultaneous interventions in health, education and nutrition. Second, the programme focused on the poor. This is in clear contrast to generalised food subsidies and other targeted interventions that dominated the anti-poverty agenda in the past. Third, the programme followed a complex system of identification and selection of beneficiaries to prevent discretionary political manipulation of public funds. Finally, an independent impact evaluation protocol proved to be critical for both improving the programme’s effectiveness and strengthening its legitimacy across different political factions and constituencies. The paper concludes that the success of Progresa-Oportunidades must be understood in a broader context, where a harsh economic and political environment, coupled with a rapid democratisation and increasing political competition, laid down the foundations for the introduction and then sustained expansion of the programme.