Objective: to study the importance of cytokines, hepcidin, a soluble transferrin receptor, iron metabolism in the development of anemia of chronic diseases in patients with malignant neoplasms and rheumatic pathology, to identify the leading factors in the development of anemia for each of the studied groups and to develop a working classification of anemia of chronic diseases.Materials and methods. 63 patients with rheumatic pathology were examined. The study group included 41 (17 men/24 women, average age 53.4 ± 4 years) patients with anemia, the control group included 22 (9 men/13 women, age 49.3 ± 1.78 years) patients without anemia. The patients (n = 63) with stage II–IV malignant neoplasms were examined. The study group included 41 pa...