Investments over the past 35 years have created a system of national and international research centers that has revolutionized the supply of improved cereal varieties to developing country farmers. The newly created scientific ability to exploit genetic resources has been the engine of productivity growth in much of world agriculture. But the success that has been attained in building research institutions has not touched all countries or farmers, nor can it be considered permanent. The financial and political environment of the past decade has halted the expansion of agricultural research capacity and the scarcity of research resources and evolving world intellectual property rights (IPR) regimes complicates the search for stable arrangements for cooperation. This paper examines the current structure and institutional capacity of the international crop breeding systems for rice and wheat. Discussions are presented within the context of a system composed of research functions spanning the basic to applied research spectrum. The model emphasizes that an efficient and stable international system may be comprised of many partner institutions, each with a limited breadth of research activities, particularly when research budgets are fixed or declining. The paper concludes with a review of some of the trends that will influence the future direction of research cooperation.