Studies of social capital have focused on the static relationship between social capital and health, governance and economic conditions. This study is a first attempt to evaluate interventions designed to improve the levels of social capital in post-conflict communities in Nicaragua and to relate those increases to health and governance issues. The two-year study involved a baseline household survey of approximately 200 households in three communities in Nicaragua, the implementation of systematic interventions designed to increase social capital in two of the locales (with one control group), and a second household survey administered two years after the baseline survey. We found that systematic interventions promoting management and leadership development were effective in improving some aspects of social capital, in particular the cognitive attitudes of trust in the communities. Interventions were also linked to higher levels of civic participation in governance processes. As in other empirical studies, we also found that higher levels of social capital were significantly associated with some positive health behaviors. The behavioral/structural components of social capital (including participation in groups and social networks) were associated with more desirable individual health behaviors such as the use of modern medicine to treat children's respiratory illnesses. Attitudinal components of social capital were positively linked to community health behaviors such as working on community sanitation campaigns. The findings presented here should be of interest to policy makers interested in health policy and social capital, as well as those working in conflict-ridden communities in the developing world.