In order to prevent or to treat anemia of prematurity, more than 800 preterm infants were enrolled into controlled studies with recombinant erythropoietin (rhEPO) during the past five years. The effective dosage seems to be within the range of 300 to 1200 IU/kg per week, markedly higher than in adults or children with anemia due to renal failure. No adverse events nor impairment of granulopoiesis or platelet formation could be attributed to erythropoietin. Statistical metaanalysis of eight controlled trials revealed an 18% reduction of transfused infants. The preventive effect was scarce in very small and very sick preterm infants, and during the first two weeks of life, when hemorrhagic anemia due to diagnostic blood loss is predominant. rhEPO treatment is one step in the concept to prevent anemia of prematurity. This concept should also include placental transfusion, minimizing of diagnostic sampling, miniaturized laboratory tests, adequate iron supplementation, and optimal nutritive protein administration.