The USAID Bureau for Democracy, Conflict, and Humanitarian Assistance Office of Conflict Management and Mitigation (DCHA/CMM) commissioned Management Systems International (MSI) to conduct research on the relationship between organized crime, conflict and fragility. The year-long research project included a literature review and country case studies in Guatemala, Nigeria and the Democratic Republic of the Congo (DRC) that examine the interaction between organized criminality and USAID conflict and fragility programming in both causal directions—with regard to how criminality affects USAID implementation and results, and how assistance affects criminality. This program-focused case study approach collected anecdotal evidence and identified lessons from Mission experience that complement previous conceptual work and has helped generate a set of general principles and options for the role and activities of development organizations with respect to organized crime.