Many conditional cash transfer (CCT) programs have important social components and, therefore, can have an effect on social capital. In 2007, we conducted a field experiment with 1451 subjects in Cartagena, Colombia. We interpret the behavior in the game as a measure of what in the literature has been called social capital. We played the game in two similar and adjacent neighborhoods. The ‘treatment’ neighborhood, Pozón, had been targeted for over 2 years by a CCT program, Familias en Acción; the ‘control’ neighborhood, Ciénaga, had not. In 2008, with the program being implemented in both neighborhoods, we played the same public goods game, and were therefore able to implement a difference in differences strategy to estimate the impact of the CCT on our measure of social capital.