The optimal target haemoglobin during treatment with recombinant human erythropoietin (r-HuEPO) is still controversial. The impact of haemoglobin on cardiovascular function or survival, on physical performance and on medical rehabilitation have to be taken into consideration. Although currently there is no solid evidence to show that haemoglobin beyond that recommended by the ad hoc committee of the National Kidney Foundation improves survival, sound theoretical arguments can be offered for this proposition, particularly in cardiac patients. It is sensible to individualize the target haemoglobin and to avoid rapid correction of anaemia.