The anemia continue to be actual problem of health care all over the world, occurring in almost half of population of terrestrial globe. The anemias are very various by their etiology, pathogenesis and clinical hematological manifestations. They are differentiated by leading pathogenic mechanism of development with purpose of choosing schemes of diagnostic and treatment. However, morphological classification and classification by color index are considered for facilitating diagnostic and differentiated diagnosis. The modern diagnosis and differentiated diagnostic of anemia bounded and unbounded with iron metabolism. The differentiated diagnosis of anemia is based on analysis of clinical, laboratory and instrumental data. In case of anemia, the blood analysis is to account indices of Hb, size of erythrocytes, their Hb saturation, average volume of erythrocytes and average content of hemoglobin in erythrocytes, color index, number of reticulocytes, etc., permitting judging about character and activity of erythropoiesis. The article presents algorithm of examination in case of occurrence of normocytic anemia, anemia in case of deficiency of diet, anemia in case of chronic renal insufficiency, hemolytic anemia; diagnostic criteria of autoimmune hemolytic anemia, inherent hemolytic microspherocytic anemia, deficiency of pyruvate kinase, paroxysmal night hemoglobinuria, deficiency of glucose-6-phosphatedehydrogenase, anemia due to primary disorders of bone marrow, aplastic anemia, hyperchrome and macrocytic anemia, deficiency of vitamin B12 (pernicious anemia) and also folic acid.