Erythropoietin therapy has not yet been well defined and its use varies according to individual neonatal care unit protocols. Prevention of the anemia of prematurity at the San Jose Hospital has changed over time. Objective: to determine the frequency of transfusion therapy related to the treatment administered to preterm infants at the Intermediate Care Unit at the San Jose Hospital between 2006 and 2008. Methodology: a longitudinal descriptive observational study was conducted in 34 patients satisfying the inclusion criteria, selected from 115 clinical records reviewed. Results: of patients who received erythropoietin 4.76% were transfused and of those who did not 46.1% required at least one transfusion. In those with a corrected gestational age = to 30 weeks who received erythropoietin, 50% did not require a transfusion, and of those who did not 50% were transfused. Those newborns with gestational age greater than 30 weeks and had received erythropoietin, 92.3% did not need to be transfused and of those who did not, 71.3% were transfused. Conclusion: it can be concluded that erythropoietin therapy reduces the need of red blood cells transfusion.