Recombinant human erythropoietin (rHuEpo) is effective in correcting renal anemia with the development of hypertension as the most frequent side-effect. Compared to hemodialysis patients with normal hemoglobin concentration, nine examined patients with transfusion-dependent renal anemia had low blood pressure in the context of high alpha 2-receptor densities and high plasma levels of catecholamines. This constellation can be explained by a defective receptor-ligand-interaction. During treatment with rHuEpo all patients showed an increase in blood pressure due to increased peripheral resistance, accompanied by a significant fall in plasma noradrenaline and alpha 2-receptor-density. There was a significant negative correlation between hemoglobin concentration and alpha 2-receptor density. We conclude that correction of renal anemia abolishes anemia-mediated disturbance of alpha 2-receptor function with the consequence of receptor down-regulation and increased vasoconstriction, which contributes to the rise in arterial blood pressure.