The prevalence of iron-deficiency anemia appears to be extremely high among female injection drug users in the inner city who have human immunodeficiency virus (HIV) and/or hepatitis C (HCV) infections. Iron deficiency and its associated anemia may contribute to reduced energetic efficiency, lower aerobic capacity, decreased endurance, and fatigue. In practical terms, the functional limitations of iron deficiency and iron-deficiency anemia may affect the ability of women to participate in work, school, social, and family activities. Iron deficiency may contribute to the cycle of poverty in the inner city by limiting the ability of women to work, earn money, and afford iron-rich sources of food. Although iron supplementation may prevent or treat iron deficiency, the use of iron supplements needs to be approached with caution in women with HIV and HCV infections.