This article examines whether conditional cash transfer (CCT) programs have had a significant effect on reducing murder rates in Mexico and Brazil, using time-series municipal-level data on murders in both countries. The findings, over the period 2005–8, show that the greater the proportion of beneficiaries enrolled in a CCT program in each municipality, the lower the number of murders. There are, however, important differences between the two countries, with a much larger effect in Brazil than in Mexico. This holds even when controlling for GDP and levels of development.