The aim of this study was to investigate the effects of recombinant human erythropoietin (rh-EPO) in patients with cancer-related anaemia. Thirty-six ambulatory patients who had malignant neoplasms and haemoglobin (Hb) values of < 11 g/dl (Pretoria is 1,310 m above sea level) entered the study. Patients with renal insufficiency, or anaemia caused by bleeding or haemolysis, and patients with iron deficiency or megaloblastic anaemia, were not entered in the study. 22 IU/kg rh-EPO was given subcutaneously 3 times/ week. The dose was escalated if Hb values did not rise after 4 weeks. All 36 patients were evaluable for toxicity. Side effects ascribed to rh-EPO were pain or discomfort at the site of injection (12 patients), heart palpitations (3 patients), skin rash (2 patients) and hypertension, deep vein thrombosis, and myalgia in 1 patient each. Thirty of the 36 patients who entered the study were evaluable for response. There were 16 females and 14 males among the evaluable patients. Median age was 64.5 years. Response, defined as an increase of Hb of at least 2 g/dl or to 12.5 g/dl, for at least 1 month, was documented in 12 patients. This was accompanied by an improvement in performance status and occurred within 1 month in 5 of the 12 patients who responded. rh-EPO has a limited but measurable therapeutic value for patients with cancer-associated anaemia.