Anemia can be the cause of heart failure, but also its consequence. The pathogenesis of anemia in chronic heart failure (CHF) has yet to be fully elucidated, but is likely to be complex. Epidemiologic studies suggest that kidney dysfunction (by reducing the erythropoietic response to anemia), inflammation (by inducing erythropoietin resistance), decreased body mass index, old age, female gender, and poor clinical status may be important factors in the development of anemia in CHF. Intestinal malabsorption, chronic aspirin use, and proteinuria predisposes to iron deficiency. Proinflammatory cytokines are likely to play a significant role in anemia in CHF by generating the "anemia of chronic illness" that is a hallmark of inflammatory conditions. Few studies have investigated the mechanisms of anemia in CHF. There is a need for such studies.