OBJECTIVES: To analyse whether the pay-for-performance mechanism proposed by the SUMAR program -a maternal and child health program implemented in Argentina in 2004 (then called Plan Nacer)- had a causal effect in reducing the infant mortality rate (<1 year), neonatal mortality rate (<28 days) and under-five mortality rate in the country. METHODS:  Because the SUMAR Program was implemented in Argentina and not in other middle-income countries, the Synthetic Control Method (Abadie and Gardeazabal, 2003; Abadie, Diamond and Hainmueller, 2014) is used to construct a counterfactual for the country as a convex combination of a set of control countries. To do this, a panel of data was constructed from information published by the World Bank, where the observation units are each of the middle-income countries and the time period analysed is 1990-2015, with Argentina being the unit treated and the year 2004 the beginning of the intervention. RESULTS: After the implementation of the incentives proposed by the SUMAR Program there was a moderate reduction in the infant mortality rate in Argentina in relation to the synthetic control. In particular, there was a decrease of 1.41 percentage points (p.p.) in the infant mortality rate, a reduction of 0.86 p.p. in the neonatal mortality rate and 1 p.p. in the under-five mortality rate. These results appear to be robust for a series of placebo experiments. CONCLUSIONS:  It is expected that the results obtained in this work will contribute to the informed debate on the role of payment mechanisms and the results of maternal and child health in low- and middle-income countries, with the intention of designing and implementing care policies more timely and efficient for the vulnerable population.