Vitamin and mineral deficiencies are a significant health problem in much of the developing world, causing illness, disability, mortality and reduced productivity. Biofortification of staple food crops has been proposed as a cost-effective solution. This paper calculates disabilityadjusted life years (DALYs) and economic surplus in order to analyze the potential health and economic benefits of cassava varieties developed to reduce vitamin A and iron deficiency in Nigeria and Kenya. Potential benefits from biofortification with vitamin A alone are estimated at $1,100 to $1,400 million in Nigeria and $67 to $81 million in Kenya, and from biofortification with both vitamin A and iron at $1,200 to $1,600 million in Nigeria and $105 to $110 million in Kenya. Costs per DALY saved are estimated at $4 to $6 for Nigeria, which compares very favorably with the costs for alternative methods such as fortification and supplementation. The estimated cost per DALY saved for Kenya is $56 to $87, which is similar to that for fortification and supplementation.