Anemia of chronic disease (ACD), also known as anaemia of inf lammation, is a common hematologic disorder accompanying chronic illnesses such as autoimmune disorders, infections and malignancies. It is second most prevalent form of anaemia after iron deficiency anaemia, yet it is commonly underdiagnosed. The current review focuses on malignancies and their influence on the erythropoietic system, the latter being mediated by tumour-derived cytokines, particularly IL-6. Three main mechanisms drive the pathogenesis of ACD: shortening of the lifespan of red blood cells, blunted erythropoietin response and disruption of iron homeostasis. The latter is mainly caused by overexpression of hepcidin – an acute phase protein which, when being in excess, denies erythropoietic cells their iron. Diagnostically, it is important to exclude other types of anaemiae, especially iron deficiency anaemia, mainly by correctly interpreting the values of seerum ferritin, hepcidin and sTfR. The ACD is usually treated by iron therapy, erythrocyte transfusion or EPO administration.