Aims Limited data exist on the epidemiology, evaluation, and prognosis of otherwise unexplained anaemia of the elderly in heart failure (HF). Thus, we aimed to determine the incidence of anaemia, to characterize diagnostic testing patterns for potentially reversible causes of anaemia, and to evaluate the independent association between incident anaemia and long-term morbidity and mortality. Methods and results Within the Cardiovascular Research Network (CVRN), we identified adults age ≥65 years with diagnosed HF between 2005 and 2012 and no anaemia at entry. Incident anaemia was defined using World Health Organization (WHO) haemoglobin thresholds ( Conclusion Among older adults with HF, incident anaemia is common and independently associated with substantially increased risks of morbidity and mortality. Additional research is necessary to clarify the value of routine evaluation and treatment of potentially reversible causes of anaemia.