Little evidence is available on whether changing global rules so as to promote human rights can enhance development outcomes. The Convention on the Rights of the Child was almost universally ratified by the mid-1990s, but it is unclear whether treaty ratification was associated with better or wider protection of childrens rights. This paper uses an instrumental variable approach to investigate whether treaty ratification was associated with stronger effort at the country level on child survival, and particularly with higher rates of immunization coverage. The paper finds that ratification of the Convention on the Rights of the Child was correlated with a subsequent increase in immunization rates, but only in upper middle and high-income countries. Treaties can promote development outcomes, but require institutional support to do so.