Micronutrient malnutrition affects billions of people world-wide, causing serious health problems. Different micronutrient interventions are currently being used, but their overall coverage is relatively limited. Biofortification - that is, breeding staple food crops for higher micronutrient contents - has been proposed as a new agriculture-based approach. Yet, as biofortified crops are still under development, relatively little is known about their economic impacts and wider ramifications. In this article, the main factors that will influence their future success are discussed, and a methodology for economic impact assessment is presented, combining agricultural, nutrition, and health aspects. Ex ante studies from India and other developing countries suggest that biofortified crops can reduce the problem of micronutrient malnutrition in a cost-effective way, when they are targeted to specific situations. Projected social returns on research investments are high and competitive with productivity-enhancing agricultural technologies. These promising results notwithstanding, biofortification should be seen as a complement rather than a substitute for existing micronutrient interventions, since the magnitude and complexity of the problem necessitate a multiplicity of approaches. Further research is needed to corroborate these findings and to address certain issues still unresolved at this stage.