Microfinance institutions (MFIs) offer targeted opportunities for the poor to generate additional income with a range of financial services including credit, insurance, savings accounts and money transfers. Aside from reducing poverty, microfinance can potentially improve health because it is the poor who are usually more constrained from health investments due to limited budgets. Furthermore, microfinancing specifically targets women, who are more likely to spend additional income on children's well-being. Finally, several MFIs have also begun to offer health-related services, such as health education, health-care financing, clinical care, training community health workers, health micro-insurance and linkages to public and private health providers. Using a new data set, this article conducts the first multi-country study of the effect of microfinance on child mortality, the health outcome, which is most sensitive to the effects of absolute deprivation. Our findings confirm that an increase in the proportion of MFI clients in a country is significantly associated with lower under-five and infant mortality rates. We conclude that if MFIs' educational and health services have indeed caused improvements in health outcomes at the community level, then it may be important for governments to complement these activities with similar campaigns, particularly in remote areas where MFI penetration is low.