This research report highlights the findings from a set of studies undertaken by the International Food Policy Research Institute, along with several national and international research institutions, to assess the economic impact of improved cultivars and management practices on smallholder farmers in the Lake Victoria Region of Uganda and Tanzania— an area where the cooking banana is both economically and culturally important. Genetic transformation is a promising alternative for improving the resistance of banana plants to the pests and diseases that cause serious economic losses, because bananas, unlike rice, wheat, and maize, are difficult to improve through conventional breeding techniques. The team of researchers posed three broad questions: What is the current level of adoption of improved cultivars and management practices, given the constraints to banana production and marketing? What are the prospects that banana growers will adopt cultivars with transgenic resistance to pests and diseases, given existing constraints? What is the potential impact on the banana industry of a range of genetic technologies now under development by national researchers? Findings confirm that smallholder farmers value the crop traits targeted for introduction by current bioengineering efforts, and that transgenic bananas have the potential to benefit the poor. The focal role of farmers in developing and promoting planting material systems and the influence of social capital on technology adoption are both demonstrated by the baseline data, with implications for the design of extension systems. The research summarized in this report is new in several respects. First, it documents the uptake of newly released banana hybrids and other recommended banana practices on semisubsistence smallholder farms in East Africa. Second, a complete taxonomy of distinct banana cultivars grown in the region has been developed. Third, the research puts existing knowledge into perspective with advanced social science methods. The findings and recommendations resulting from this study will be useful for policy decisions in the region, contributing initially to technological development and dissemination, and ultimately to increased crop productivity.