Market failure for nutritional attributes of foods leads to underinvestment in crop breeding to enhance nutritional content of foods.  As awareness of the importance of micronutrient deficiencies in the diets of poor people has grown, public investments in research to create biofortified staple crops have increased.  The potential for this new approach is assessed in two ways.  First, an examination of lessons from established interventions to address micronutrient deficiencies shows where and how biofortification can complement existing interventions and provides guidance regarding potential hurdles to successful implementation.  Second, the potential for different crop-breeding technologies to biofortify crops is examined, and the advances that can only be achieved through application of modern biotechnology are identified.