This review article summarizes the current medical literature reporting on the prevalence and prognostic significance of anemia in patients with heart failure. Almost all currently available data indicate that anemia is common in heart failure populations, with the majority of studies indicating prevalence >20%. Anemia appears to be more highly prevalent in patients with advanced age, with more severe limitations in functional capacity, and with greater severity of co-morbid chronic kidney disease. In most reported studies anemia is an independent predictor of increased mortality risk and increased risk of hospitalization for heart failure. These data provide the rationale for interventional treatment trials to determine if anemia is in the causal pathway for disease progression and increased mortality risk in HF patients.