Aplastic anemia (AA) is a disease of multipotent hematopoietic stem cells which causes hypocellular or acellular bone marrow. In the peripheral blood, it gives a picture of anemia, granulocytopenia and trombocytopenia. The occurrence of this condition is 0.002 – 0.005% of inhabitants annually. It is divided into inherited and acquired, which is further divided as idiopathic or secondary (which develops as a consequence of various infections, drugs, radiations and toxins). It is diagnosed with bone marrow biopsy but the severity of the disease is determined by Camitta criteria based on peripheral blood sample results such as erythrocyte, reticulocyte, leukocyte and thrombocyte count. Etiopathogenesis of aplastic anemia is based on autoimmune basis mediated by T lymphocytes and the lymphokines they secrete which cause the destruction of hematopoietic stem cells with the complete reduction of hematopoiesis. Most common clinical indications that will point to the development of this disease are symptoms of anemia, easy bruising, prolongated bleeding and in some patients frequent and severe infections. There are different methods to treat aplastic anemia. The most important and the best one is allogeneic hematopoietic stem cell transplantation from either a related or an unrelated donor which enables restoration of hematopoiesis in patients that are suitable for this treatment option. Along the transplantation, a method of immunosuppressive therapy has been developed with drugs such as antithymocyte globulin and cyclosporine, and in recent years eltrombopag, a thrombopoetin receptor agonist, is used in treatment of AA. While on immunosuppressive immunotherapy, supportive therapy with irradiated doses of erythrocytes and trombocytes is extremly immportant for patients with severe anemias and thrombocytopenias.