Anemia has been demonstrated to be a common finding in patients with heart failure (HF). Previous studies in hospitalized patients with HF have found a prevalence of anemia ranging from 15% to 63%. More importantly, anemic patients with HF have increased morbidity and mortality. The mechanisms underlying anemia in HF are multifactorial, involving mild to moderate forms of anemia of chronic disease and ferropenic anemia. The clinical impact of iron supplementation in HF patients who have a relatively preserved renal function and either chronic disease anemia, ferropenic anemia or both remains largely unknown. The route of iron administration that could be most clinically effective is also unclear. Thus, the primary aim of the IRON-HF study is to assess the effects of iron supplementation alone (IV or PO) on parameters of functional capacity in HF patients with anemia with decreased availability of iron.