Numerous evaluations of the Bean/Cowpea Collaborative Research Support Program (CRSP) have documented CRSP contributions to food production and availability with impacts valued in the millions of dollars in developing countries as well as in the US. These reports emphasized collaboration as a critical factor in the success that emanated from CRSP research and training. Real collaboration among males and females across disciplinary, national, ethnic, cultural, and language differences is not easy. This review of CRSP experiences in building productive collaborations gives actual case studies, including some failures, and discusses lessons learned in the process. The importance of wide participation, shared resources, and facilitated interpersonal relations to back up the dedication and commitment of the participants in emphasized. The program represents an investment of the US Agency for International Development with contributions in excess of 25 percent from participating US and Host Country institutions.