Resumo:The Cadastro Único is the main registry for the purpose of programmes and policies directed at low-income populations in Brazil. It was formally created in 2001, in the context of the consolidation of four different cash transfer programmes: School Grants Programme (Programa Bolsa Escola), Child Labour Eradication Programme (Programa de Erradicação do Trabalho Infantil — PETI), Gas Voucher (Vale Gás) and Food Grant (Programa Bolsa Alimentação). The registry intended to unify, in a single database, the individual registries of these programmes, thus minimising the data collection effort. (…)