This Working Paper completes the One Pager with the same name, both from the International Policy Centre for Inclusive Growth (IPC-IG). It summarizes general characteristics and history of Brazil’s Unified Registry (Cadastro Único). Its main difference from most targeted registries around the world is that income is declared by families themselves. It also investigates the role of the national public bank, Caixa Econômica Federal, in developing and maintaining Unified Registry’s systems and databases.