Anemia is often encountered in clinical practice. It has to be noted that anemia is only a symptom of an underlying disease. Early, correct and consequent diagnosis is crucial in order to prevent late detection of fatal disease or to prescribe contraindicated therapy. The combined use of a morphologic and physiologic classification allows for understanding and correct classification of anemia in a specific patient. In this respect, the determination of reticulocyte counts is of special importance. Further targeted biochemical, morphological and immunological analysis leads to the definitive diagnosis of anemia. A large proportion of the anemias can be diagnosed and treated by the general practitioner. However, involvement of a haematologist is recommended in several clinical situations, such as newly diagnosed haemolytic anemia, as well as in patients with complex, equivocal or therapy-refractory anemia or certain normocytic hyporegenerative anemias. This paper presents a differentiated stepwise approach in diagnosing anemic disorders.