Reducing malnutrition in Africa has both intrinsic and instrumental value. Better nourished populations are more economically productive. Children better nourished during the first 1000 days (in utero and the first two years of life) will be more productive as adults, increasing country GDP. Malnutrition costs African economies between 3 and 16 percent of GDP annually. For an illustrative set of 15 African countries, meeting the 2025 World Health Assembly target for stunting will add 83 billion dollars to national incomes. Interventions that prevent malnutrition are excellent investments; for a typical African country, every dollar invested in reducing chronic undernutrition in children yields a $16 return. Reductions in malnutrition will occur most rapidly when countries undertake investments in both nutrition-specific and nutrition-sensitive interventions.