Background/Aim. Anemia is one of the most frequent hematology disorders in patients with malignant diseases. It has a great influence on reduction of the quality of life, so it requires early diagnosis and an adequate treatment. The aim of this study was to present and analyze the treatment of anemia using red blood cell transfusions in patients with malignancies, to analyze adequate use of red blood cell transfusions according to hemoglobin concentration, and also the influence of the treatment of malignant disease on the level of anemia and use of red blood cells transfusion. Methods. This retrospective analysis included the data on the use of red blood cells in Oncological Clinic of Clinical Center Niš in a period from the 1st January 2008 to the 31st December 2008. Results. None of the patients received the whole blood. In this period, 735 patients received 1,006 units of red blood cells (red blood cell concentrate, resuspended, washed, filtered). An average use of red blood cell transfusion was 1.37 unit per oncological patient who received transfusion. The use of red blood cell units was adequate (87.60% of patients received transfusion of red cells when Hgb < 80 g/L). During radio- and chemotherapy we noticed a decrease of hematological parameter values. The patients of the experimental group were dependant on red blood cells transfusion. Statistically, a significant decrease of hemoglobin level was observed in patients treated only with radiotherapy who are the greatest consumers of red blood cells. Two patients were registered who more likely to have febrile nonhemolytic transfusion reactions. Posttransfusion alloimmunization occurred in 0.68% of the patients. Conclusion. The use of red blood cells in oncological patients is in compliance with the up to date tendencies and recommendations published in clinical guidelines. For the purpose of efficient transfusion support in patients with malignant diseases, we have to follow the newest knowledge and attitudes about clinical use of blood products.