Conditional cash transfer programs are innovative social safety-net programs that aim to relieve poverty. They provide a regular source of income to poor families and are “conditional” in that they require poor families to invest in the health and education of their children through greater use of educational and preventive health services. Brazil’s Bolsa Família conditional cash transfer program, created in 2003, is the world’s largest program of its kind. During the first five years of the program, it was associated with a significant 9.3 percent reduction in overall infant mortality rates, with greater declines in postneonatal mortality rates than in mortality rates at an earlier age and in municipalities with many users of Brazil’s Family Health Program than in those with lower use rates. There were also larger effects in municipalities with higher infant mortality rates at baseline. Programs like Bolsa Família can improve child health and reduce long-standing health inequalities. Policy makers should review the adequacy of basic health services to ensure that the services can respond to the increased demand created by such programs. Programs should also target vulnerable groups at greatest risk and include careful monitoring and evaluation.