For the last 12 years, scientific evidence has mounted linking Helicobacter pylori infection with iron deficiency and iron deficiency anemia. Reports from around the world on several cases of iron deficiency anemia refractory to iron supplementation among children infected with Helicobacter pylori, most without evident ulcers, clearly indicate that such cases have been cured of their anemia after receiving a course of Helicobacter pylori eradication therapy. Several studies based on national surveys, including one on the U.S. National Health and Nutrition Examination Survey data and conducted by the authors of this proposal, have found an association between Helicobacter pylori infection and the levels of iron stores. However, these studies fail to demonstrate that anemia follows Helicobacter pylori infection. Moreover, most previous research has been conducted outside of the contiguous U.S. and has not included young children, one of the high-risk populations for iron deficiency and iron deficiency anemia. Data on this age-group is most needed to develop sound public health interventions.