Iron deficiency is considered to be one of most prevalent forms of malnutrition, yet there has been a lack of consensus about the nature and magnitude of the health consequences of iron deficiency in populations. This paper presents new estimates of the public health importance of iron-deficiency anemia (IDA), which were made as part of the Global Burden of Disease (GBD) 2000 project. Iron deficiency is considered to contribute to death and disability as a risk factor for maternal and perinatal mortality, and also through its direct contributions to cognitive impairment, decreased work productivity, and death from severe anemia. Based on meta-analysis of observational studies, mortality risk estimates for maternal and perinatal mortality are calculated as the decreased risk in mortality for each 1 g/dl increase in mean pregnancy hemoglobin concentration. On average, globally, 50% of the anemia is assumed to be attributable to iron deficiency. Globally, iron deficiency ranks number 9 among 26 risk factors included in the GBD 2000, and accounts for 841,000 deaths and 35,057,000 disability-adjusted life years lost. Africa and parts of Asia bear 71% of the global mortality burden and 65% of the disability-adjusted life years lost, whereas North America bears 1.4% of the global burden. There is an urgent need to develop effective and sustainable interventions to control iron-deficiency anemia. This will likely not be achieved without substantial involvement of the private sector.