The aim of this study was to determine whether the preoperative administration of recombinant human erythropoietin (rHuEPO) could increase the rate of autologous blood donation and reduce the perioperative need for homologous blood in anaemic patients with cancer. Twenty-two anaemic (haematocrit less than 34 per cent), iron-deficient (iron less than 700 micrograms/l) patients, with gastric or colorectal cancer scheduled for elective surgery, were allocated randomly to two groups. The first (n = 11) received iron saccharate 200 mg/day intravenously for 12 consecutive days. The second (n = 11) received rHuEPO subcutaneously (300 units/kg as first administration, and 100 units/kg 4, 8 and 12 days later) with supplemental iron. On days 4, 8 and 12, if the haematocrit was greater than 34 per cent, patients donated one unit (350 ml) of autologous blood. In the iron group the mean haematocrit did not change from admission (31 per cent) to day 12 of treatment (31 per cent), and no patient could donate autologous blood. In the rHuEPO group, eight patients donated two units of autologous blood and three donated one unit. Four patients in the iron group received perioperative transfusion of homologous blood compared with none in the rHuEPO group. Administration of rHuEPO facilitated the donation of autologous blood and reduced perioperative homologous blood transfusion in anaemic patients with cancer.