Erythropoietin can be successfully used in the treatment of anaemia induced by chemotherapy and radiotherapy as well as for the treatment of anaemia induced by malignant disease without previous chemotherapy of radiotherapy. Erythropoietin administered during chemotherapy is effective in 50-70% patients, it has a more marked effect as a supplement to chemotherapy with cisplatinum and carboplatinum than non-platinum regimens. Erythropoietin reduces the consumption of red cell concentrates during chemotherapy on average by one half. Long-term administration of erythropoietin in anaemia caused by malignant disease alone proves most effective in multiple myeloma and in chronic lymphatic leukaemia or in non-Hodgkin lymphomas with a low malignity. The therapeutic responses defined as independence on transfusions and a rise of the haemoglobin level by at least 20 g/l, as compared with the pretreatment value, can be achieved in 60 to 80% of the patients. Erythropoietin is much less effective (10-20% therapeutic responses) in myelodysplastic syndrome, in myeloproliferative diseases or in aplastic anaemia. The authors give an account on the effectiveness of erythropoietin in different indications.