Since CGIAR centers have been in existence for a number of years, this paper addresses the impact of these centers on national research and extension programs and crop productivity. The study estimates that the CGIAR Centers have had a positive impact on investment in national research programs in each of the crops for which CGIAR crop programs exist except cassava. Estimates for livestock and horticultural crop research programs show a significant positive CGIAR impact as well. National extension spending is also stimulated by CGIAR programs. These estimates are based on an econometric specification that takes into account the impact of several economic development aid initiatives in addition to the activities of the CGIAR impacts. The study estimates that CGIAR Center programs have had significant impacts on crop productivity for maize, millets, sorghum, rice, wheat, beans, cassava and potatoes in all the regions studied. National research programs have had a positive impact on crop productivity in most of these crops as well. In addition, national extension programs have been productive in some crops. These estimates are based on crop production data in 25 countries.